Hello Liyany, WR304,
you're right, it was just that the free hub body was REALLY stuck: installing a cassete and hammering on it did the trick. There was corrosion in the steel spacer inside the hub body which kind of glued it in the hub's axle. I've bought this unity second hand and although it was shiny I believe it has never seen any internal maintenance. I've ordered new bearings and will rebuild it before starting to use it.
Thank you guys for your comments, they were really useful.
It sounds like it's had a hard life. If the rest of the hub is in that bad a state are the electronics still in working order? If there's a torque tube issue then it will need to go back to Saris to be repaired which is quite expensive.
Originally Posted by laudares
Have you checked the powertap hub's torque offset to see if it's still close to 512? With an older hub you'll need a little yellow computer or Cycleops Joule 2.0 to be able to display the figure. Garmin Edge head units only display the torque offset for newer firmware versions of the Powertap hub.
For $350 saris will replace all the internals and the free hub body. It's expensive yeah, but considering you basically get a brand new $1600 hub back for $350 it's not bad at all. As a result you can keep a power tap hub running for years without too much continued expense. Hopefully my quarq doesn't end up being more expensive...
Originally Posted by WR304
I want to dismantle completely the hub to try to repair myself, there is any way to get out the torque tube?
I have power tap hub wheelset for my road bike but I don't have it on my 2012 Cannondale Flash 29'er. Would you suggest sticking with Powertap and just getting a back wheel and/or buying cranks with power built in for my Cannondale?!
I've been accumulating and training by power now since July. I use WKO+ 3 software and so far have found it very interesting. All my workouts are super specific and I have enjoyed it but this type of training program also makes it tough to ride with others when I am doing very specific workouts in varous training zones! WR304 and others... I may have to pick your brains now and then on the MTB side with power if I go there.
One things I've noticed on my PowerTap G3 hub is that the cadence it gives me seems to be pretty consistent as well as the mileage when I'm on a trainer. If anything it seems a little under represented when riding on the trainer. Often times I do what feels like a 1 hr ride and what feels like the equivalent of a 15.5 - 17 mph pace and it will calculate it as a 14- 14.5 mile ride.
I have a Powertap on my MTB, however, I would probably get a Quarq if I did it over again. You can get a used Quarq off ebay for about $1000. The biggest thing for me is that with my Powertap, I know it's just a matter of time before it needs a $300 service. I have not had any issues with it so far, I've ridden in absolute downpours, mud without any loss of power data or the insides getting wet.
Trainers are not calibrated to be the same as the road, paying attention to time & power is all you need to pay attention to, not distance.
I've got a Quarq Quattro but never got round to using it. The way I view it is that you should decide between a MTB Powertap or Quarq Quattro depending upon whether weight or gearing options are more important to you. Unless you're unlucky they both ought to be fairly reliable.
Originally Posted by TritonBill
The MTB Powertap isn't currently available in the lighter G3 version. The Powertap Pro MTB hub with its bulky custom brake rotor adds quite a bit of weight onto the bike compared to a typical freehub and your choice of brake rotor. The Quarq Quattro in contrast isn't much heavier than the SRAM X0 chainset that it's based on.
Powertap Pro MTB hub including rotor. Claimed weight 680g
DT 240s hub 240g & Shimano XT Icetech Rotor 115g. Claimed weight 355g
DT Swiss - 240s
The Quarq Quattro BB30 has a claimed weight of 723g, heavier than an aftermarket chainset but around the same as the SRAM X0 BB30 chainset that it's based on.
SRAM S2275 MTB Power Meter
SRAM X0 2×10 Official Photos and Specs - Bike Rumor
Although you'd think that makes the Quarq Quattro a clear winner it has one big issue. It uses the SRAM 120/80 BCD standard so the smallest inner chainring you can fit is a 26T. Used with 29" wheels that means you're potentially going to run out of gears if there are a lot of long steep climbs nearby. The Powertap Pro MTB hub lets you use any cassette and chainset so the gearing of your bike can be set appropriately when needed.
Mileage recorded on a turbo trainer doesn't mean much. (if you're trying to compare between MTB and road rides then the relative distances covered there don't mean much either) I'd concentrate on time and power output instead as they will be comparable between turbo sessions. If you're able to complete the session with a higher power output then it shows progress. Aiming to do a session of a set time duration on the turbo, rather than a set distance, would be the normal way to approach it.:)
Have a look at this thread too. It has some more discussion and various power files attached also.
I've been meaning to write a post about marking up an MTB power file from scratch for ages now but haven't managed to finish it yet. When I crashed four months ago (18 August 2012) it turns out that I actually dislocated my left clavicle and badly fractured my left femur (where it had been broken before previously). I haven't been able to ride at all since then. I've had an operation to have an external fixator put on the thigh in order to try and make the bones knit back together but it's likely to mean another six months off the bike still. There's no set date when it will be healed.:(
This youtube video is a webinar by Hunter Allen about using WKO+ 3.0. It has some interesting parts in. The video itself is quite long so I'd suggest downloading it with a program such as Freemake video downloader. You can then watch it back in short sections which are easier to digest. Watching a section of video, trying the feature in WKO+ 3.0 and then moving onto the next part of the video helps to make sense of it. :)
The last question made me laugh. "What are the little triangles for in the quadrant analysis screen?"
Hunter Allen's answer: "We never worked out what they were for either." :)
<iframe width="560" height="315" src="http://www.youtube.com/embed/zWE8cc24Ttc" frameborder="0" allowfullscreen></iframe>
Learn the secrets to unlock your power meter data using TrainingPeaks WKO+ software by Hunter Allen - YouTube
Free Video Downloader | YouTube Downloader | FREE Download
I really appreciate the useful information in this thread. Can anybody comment on their experience with 26x38 gearing on a 29er in long endurance races with big climbs (50+ miles)? Do you find the 26 to be low enough (say for Leadville or Whiskey 50) or are a lot of competative people running more? For reference, I'm a fairly strong roadie (FTP ~300 and ~145 lbs), but I do like to keep a cadance of 90 or when climbing. Will I find myself slow-grinding/standing up a lot with 26-38 on a long hill climb?
Originally Posted by WR304
I'm building up my first 29er HT after coming off a year of nothing but road racing. Before that I've only rode heavy 26ers for trail riding so I have no point-of-reference for 29er gearing. I'm trying to decide between the PowerTap and Quarq. This is a huge amount of money, so I'm concerned about the limitations of both.
WR304 had described the tradeoff very well above. WR304, you sound like a fairly strong rider, but also sound like you don't think 26T front chainring is low enough. This is making me nervous of choosing the Quarq, although it was my first choice due to lower weight and choice of rear hub vs PowerTap.
I've been looking and looking on eBay, but no sign of any used MTB Quarqs. Am I looking for the wrong thing? There are many used road Quarqs for around $1000, used MTB Quarqs or MTB PowerTaps seem to be rare.
Originally Posted by wetpaint
You just have to save the search and watch them. There seems to be a few of them popping up a month. There is also one for sale on weightweenies for around ~$1200
I wrote that post a while ago. You also have a few new MTB power meter options being released at the beginning of 2013 to consider now: You have the Rotor power meter which costs about the same as a Quarq. The Rotor MTB power meter uses 104/64 BCD chainrings, has strain gauges in both cranks for measuring left/right power and you can use it with round or oval chainrings. It looks really interesting.:)
<iframe width="560" height="315" src="http://www.youtube.com/embed/bO78H9CtSz0" frameborder="0" allowfullscreen></iframe>
Rotor Power Meter Crank - YouTube
First look at new ROTOR Power Meter | DC Rainmaker
ROTOR PowerTechnical Specifications - ROTOR Power Cranksets
There's also the Stages power meter which fits into just the left hand crank, allowing you to use your choice of wheels and chainset. It's reasonably priced and only adds 20g of weight. There are plenty of MTB crank options available too. The accuracy of it appears to be being called into question however. Because the Stages power meter only measures the torque generated by your left leg it doubles the left legs power output as an estimate of power output from both legs. Have a look at the links below:
Stages Power Meter In-Depth Review | DC Rainmaker
StageONE Power Meter... I'm Stoked!
Choosing the appropriate gearing is one of those things where there's never a one size fits all answer. If you're a good climber then the 26 tooth inner ring is probably a non issue on 95% of climbs. If you never needed to use your granny ring on a 26" bike then a double chainset with 39/26 chainrings will be fine. Your w/kg is a lot higher than mine ever was last year so that's a big advantage straight away.:)
Using Sheldon Brown's gear calculator you can compare different gearing combinations. As a very rough estimate, if you had the same chainrings and sprockets fitted to a 26" wheeled bike as to a 29er you would need to use one sprocket lower on the 29er's rear cassette to be in the same gear as you would be on a 26" wheeled bike. The chart below is comparing 39/26 chainrings and a 11-36 cassette with 29" wheels to a triple chainring 44/32/22 11-32 cassette which was fairly standard a few years ago before double chainrings became popular.
Sheldon Brown's Bicycle Gear Calculator
Whether you'd get up a particular hill in a 26x36 bottom gear on a 29er really depends on the climb. There are some climbs which are ridiculous regardless of the gearing.
Vuelta a Espana 2012. Stage 16. Last km. - YouTube
The chart below is my best power outputs at different durations for 01 January 2012 to 18 August 2012. 18 August 2012 was when I crashed and broke my leg so that was it for 2012.:(
When you look at the same chart for 2011 it's clear from the power numbers that I had improved, especially over longer time periods which is what I was concentrating on. It's easy to get sucked into just looking at the 5 second, 1 minute, 5 minute and 20 minute durations in WKO+ 3.0 so having your own chart to keep track of the other time durations that may be more relevant is useful to have.:)
If you're going to be doing regular tests throughout the year then I think it's worth doing one at the start of the year too. That way you have an idea of what you can expect your trough to peak power outputs to be over the year.
If you look at this chart of my 20 minute FTP test results between 01 January 2011 and 18 August 2012 (when I crashed and broke my leg) you can see how the initial test in January 2011 wasn't great. After being ill over Christmas and doing very little cycling for the previous few months, due to bad weather, it took a while to build up my fitness levels again. After that rapid increase in the first part of the year the test results plateaued. Despite continuing to ride regularly I didn't make any major gains in 20 minute power output in the second half of 2011.
In January 2012 by contrast I'd kept riding and started the year at a higher fitness level. Both the initial test in January 2012 and my peak fitness in August 2012 were significantly better than the same dates in 2011.
I've also added monthly hours riding to the chart so you can see my power output plotted against that.:)
If you train for a certain duration then you're likely to find yourself improving at that duration but you have to be careful not to get too carried away with that, especially if power outputs below an hour aren't the main priority. Adding a report to show your longer duration power outputs can be helpful to stay focused.:)
Looking at the big picture like this I'm quite surprised by some of the trends. It's a good example of what you can expect if you follow the philosophy of "just ride lots". I didn't really have a set plan or set goals. The only real aim was to be fit enough to get round the road club runs without getting dropped. I got hammered mostly in that respect. There were a few rides where I did make it to the coffee stop still in contact with the group though, so it was partially successful.:)
For training I was doing more or less the same thing each year by starting off with hard rides in January, including some interval sessions and getting a good fitness improvement by March - April. In past years when I was racing I'd have been "racing myself fit" from that point on. As the weather improved I was losing interest in training for the sake of it and spending more time riding trails offroad instead. Enjoyable and good for bike handling but not very focused on fitness. In my power data my offroad rides always have a lower power output than road miles, which increases the amount of time spent in the lower power zones.
The (in)frequency of interval sessions is what I find surprising. I'd have thought that I would have done more than I actually did. I tend to have themes for each year. All I did outdoors was 6x4 minute intervals in 2011 These were 4 minutes on followed by 4 minutes off. In 2012 I only did 3x9 minute over-under intervals outdoors. Of the two types of intervals I think the 3x9 minute intervals worked better for what I was trying to do. Outdoors intervals were always part of longer rides. I'd usually do intervals in the first hour and then another 2-3 hours in the hills afterwards.
If you're using the Coggan power levels then 20 Minutes x 0.95 is supposed to be a rough estimate of your best 1 hour power. It seems to depend upon individual physiology how well it actually aligns though. 95% of my best 20 minute power is a lot higher than I can actually manage for an hour flat out. Along with the 20 minute tests I also did several 1 hour tests during 2011-2012 to see how they compared. You can see from the table above that my actual 1 hour power was a lot lower than the 20 minutes x 0.95 would suggest. The 1 hour power results were as good as I could do at the time. I definitely wasn't holding back.
There are other test protocols too. If you read any of the Chris Carmichael books then they use the CTS test instead. That will give you different power results to 20 min x 0.95 so the specific training zones aren't interchangeable. This PDF sets out that test procedure and explains what a under-over interval consists of.:)
My favoured turbo training session (done when the weather was bad or my mountain bike was broken) consisted of this 1 hour interval session by Dr Andrew Coggan. It's a routine that I've done quite frequently in the past. I like it because it breaks the turbo training time into manageable chunks. The wattage figures are just his figures, you aim for your own zones (heart rate or power) at those durations. 30 second sprints are flat out.
"Seriously, the best season I've had in recent years followed a winter
during which I did the following '90/90'90' workout 3 d/wk:
5 min w/u
20 min @ 275 W
5 min easy
5 min @ 325 W
2.5 min easy
5 min @ 325 W
2.5 min easy
0.5 min at 500 W
2 min easy
0.5 min at 500 W
2 min easy
0.5 min at 500 W
2 min easy
0.5 min at 500 W
2.5 min easy
5 min warm-down
The '90/90/90' refers to the fact that (almost by chance) the powers
used were about 90% of the best that I could produce for that duration
when at peak fitness. That made the session challenging enough that I
didn't lose too much fitness over the winter, but not so hard that I
ever dreaded the workout or burned out from doing it." Andrew Coggan
Taken from the big Slowtwitch thread on Powertap hubs. Some notes about MTB Powertap hubs: :)
"We do intend to make a 140mm rotor but first we need to build an MTB hub around the G3 platform.
All PowerTap hubs are extremely water proof. For better or worse we have a history with this issue that has lead to some unique insight into overall robustness and durability of all our hubs. The G3 represents further refinement in this area and all our MTB hubs are now being built with G3 internals that offer this advancement. "
CycleOps Product Manager
Follow me on Twitter @powertappro
Saris Cycling Group
Official PowerTap Thread (Page 6): Triathlon Forum: Slowtwitch Forums
So does that mean I get G3 internals if I send my Powertap back? My ZO has risen to 540 from 512 last year. Power is still where it should be, but it's just a matter of time before I have to send it in for rebuild.
I thought it was interesting that the updated internals were specifically mentioned in that thread. I'd guess that means new hubs will definitely be to the latest specifications. They really need to get on with releasing a full G3 MTB hub to match the road models also. That would save weight and counter one of the main criticisms of the current MTB Powertap hubs.:)
Originally Posted by wetpaint
I'm not sure whether you're guaranteed the latest internals when being serviced. It's probably going to depend what the Powertap service centre has available as spares. If they've got old torque tube assemblies then those would be probably be used up first.
I'd have thought the best bet would be to contact Powertap and see what they say. In the UK you have to email and request they send you a servicing number for any work on a Powertap anyway.:)
Yeah, I'll probably give them call to see about sending mine in (USA). I have to try to get the timing in so I don't miss any race data. I'm not too concerned about the weight, even though the MTB version is pig. It'd be nice to have the separate electronics pod in case it goes bad again in the future.
I just called and got an RA # to send my powertap back, Saris confirmed they're putting G3 internals in for rebuilds! That makes it much easier to stomach the $350 rebuild.
The good thing about a full Powertap rebuild with the torque tube being replaced is that you're literally getting a new hub back. All they keep is the hollow exterior hub shell that the spokes are laced to. The torque tube (which is everything inside the hub including hub bearings, axle etc) is unscrewed and a new assembly is screwed into the hub shell.
I really ought to get my hub looked at too. It went haywire on 12 August 2012 after being caught in a ridiculous rain storm. I was out with the road club when the rain started. The club stopped to shelter under a rural petrol station's awning it was so bad. As the rain kept hammering down all these bikers came and stopped to shelter too, then several mods on scooters came and stopped too. As the rain continued lots of other cyclists were stopping too until eventually the forecourt was filled with all sorts of bicycles and motorbikes with everyone just looking out at the downpour. In the end we had to set off in the rain/ floods and then my Powertap started giving random power readings.
After being dried out that night it appeared to be working ok again in the days afterwards. I crashed shortly afterwards 18 August 2012 though, so it hasn't been used since then. It would probably make sense to get the hub serviced whilst I can't ride.:)
Re: PowerTap Disc
WR, you crashed in August and still can't ride?? I hope you get back out there this year!
Sent from my DROID BIONIC using Tapatalk 2
I'm normally quite good at crashing (lots of practice ;) ). The problem with this crash was that I was still attached to the bike so couldn't tuck and roll. I was trying to accelerate across a roundabout when my right foot came unclipped from the SPD pedal under full power. My right foot flew forwards and jammed between the front wheel and fork, breaking several spokes in the front wheel.
With the front wheel still completely locked by my foot the bike then flipped straight over at 16mph. From the damage spread evenly across the front of the handlebars, brake lever clamps and stem faceplate it looks like the front end was driven straight down into the tarmac.
I landed on my left shoulder, left hip and left thigh, dislocating my left clavicle and fracturing my left femur. I didn't slide at all, just a hard impact. Fortunately a passer by was able to pull my trapped foot out of the front wheel so that I could crawl out of the busy main road and lie down.
My left leg was a mess to begin with. It's had lots of previous operations and a major fasciotomy so there's barely anything left of the thigh besides scar tissue. My left leg is also paralysed from the knee down with poor circulation. When I re-broke the femur it wasn't a healthy bone, imagine a rotten branch, hollow on the inside with a MRSA bone infection just to make it more hassle. With a normal broken femur you can put a titanium pin inside for a quick repair. Because of the bone infection the hospital don't want to risk that as operating would make it flare up again.
The hospital have instead been trying to encourage new bone growth using an external fixator and the Ilizarov technique of pulling the two bone ends apart. This link explains how the Ilizarov technique encourages bone growth.
About Limb Lengthening
This is what is being tried with my broken left femur at the moment. There's some bone growth on the inside but the outside of the femur is still stubbornly refusing to grow back currently. That's why it's taking so long. There isn't a set time frame for these things.:)
Wheelbuilder.com have released a SRAM XX1 compatible freehub body for the Powertap hub now: :)
I have the Wheelbuilder XX1 body on my new G3 hub. It seems to have some problems with the bearing as I am now on my third set of bearings on only 4 rides !!!. The inner bearing last from 1-2 rides and then it crashes. To me, it looks like wheelbuilder not have made a proper assembly as there is a little play between the “alu spacer” and the bearings. This result, that the bearings comes in tension when I tighten the wheel in the frame with the 12 mm thru bolt.
Do you or any other have any experience with the XX1 body from Wheelbuilder ??
I've got the Wheelbuilder 142x12mm axle but not the XX1 body. That's not very good if the bearing is only lasting one ride before failing. What have Wheelbuilder said about it?
Originally Posted by Henrik J
Powertap have been dropping some heavy hints that they're going to be releasing an updated Powertap MTB hub with DT Swiss star ratchet internals, 142x12mm axle and XX1 freehub as original options:
"The GS hubs will feature lots of DT Swiss hardware, including the axles, bearings, star ratchet, freehub body, end caps, and straight-pull flange. The front hub is essentially a stock 240s DT Swiss model.
What DT Swiss hubs mean for mountain bikes and disc brakes
PowerTap’s move to DT Swiss hub internals will undoubtedly be a boon for durability and perceived quality, but the collaboration could also have big implications for the power meter company’s stagnant mountain bike range, given the new engineering resources.
The biggest challenge to integrating a disc mount on any PowerTap hub has always been working around the large-diameter electronics cap, which, on the latest G3 and GS hub, houses the battery, wireless transmitter, and micro-USB port for updating the firmware. As a result, PowerTap’s current mountain bike hub relies on a proprietary two-piece rotor and is limited to a 160mm diameter.
PowerTap product manager Jesse Bartholomew told BikeRadar that the company is already working on a new disc-compatible model based on the GS, with the same DT Swiss star ratchet internals, axle, and bearings.
This also means instant SRAM XX1 XD driver body compatibility and implies a wide range of axle fitments for both quick-release and thru-axle applications. Riders seeking a faster engagement speed would also have the option of installing DT Swiss 36-tooth ratchet rings.
Coupled with the already available 11-speed freehub bodies, this means PowerTap’s upcoming new disc hub could find use on disc-equipped road and cyclocross bikes, as well as mountain bikes.
Bartholomew said he expects that the new hub will still rely on a proprietary rotor interface. However, the design isn’t finalized, so we're still hoping for a disc-specific electronics cap and standard six-bolt rotor compatibility.
Powertap GS road hub showing the new DT Swiss star ratchet internals