After months of procrastination I finally have a working design. I would like to present my work in progress:
Fooly's Major Glory - 650b Titanium Soft Tail, Rohloff/Gates belt drive.
If I can get my butt in gear, I should have this frame completed by end of January 2013. And parted up by end of February or early March, just in time for the Sol-Cal Kenda Cup.
Over the next few weeks I hope to document some of the progress on the project. I hope you enjoy it.
Dan "Fooly" Acosta
Edit: added some pictures of the parts I've been collecting.
Edit: added some pictures of some of the custom parts I've been making
Edit: added some pictures of more bits that came in. Added the Chain Stay and Seat Stay tube from the tube bender.
It's my understanding Rohloff are super picky about properly stiff chainstays when using a belt. Are you confident that your design won't allow tension to change too much?
It's my understanding Rohloff are super picky about properly stiff chainstays when using a belt. Are you confident that your design won't allow tension to change too much?
I suppose it does "pivot" around the bottom bracket... and the new/current CenterTrack belts should be more tolerant of changes in tension? *shrugs*
Since it is a soft tail, I am not getting a lot of rear wheel travel. From the neutral position (mid travel) the chain is at its longest. To the fully extended position I am calculating the chain line to shrink by about 0.040 inches. And to the fully compressed position the chain line will shrink about 0.065 inches. My test bike with a more traditional rigid frame design this is just a few turns of the adjusting screw. My tests seems to show this will work just fine. May not be the best for the belt, but I confident that this will work better in the long run than the traditional chain.
Seriously, I think you are going to have major problems with a belt on a softail. Even very small amounts of chain growth are going to be murder with those tension requirements. But you can always just throw a chain on it, so it's not the end of the world if it doesn't work out.
Since it is a soft tail, I am not getting a lot of rear wheel travel. From the neutral position (mid travel) the chain is at its longest. To the fully extended position I am calculating the chain line to shrink by about 0.040 inches. And to the fully compressed position the chain line will shrink about 0.065 inches. My test bike with a more traditional rigid frame design this is just a few turns of the adjusting screw. My tests seems to show this will work just fine. May not be the best for the belt, but I confident that this will work better in the long run than the traditional chain.
You need to learn the difference between chain line and chain growth.
It is not just chain growth than can cause issues with belt drive. Some rigid frames have problems because of lateral and/or torsional flex.
mtbtires.com
The trouble with common sense is it is no longer common
What rear belt sprocket are you going to use? Rohloff won't sell theirs unless the frame is certified by Gates...and even then they won't sell the adapter, you have to ship you hub to them to get it fitted!
As far I understand hub warranty is also void if you use anyone elses sprockets because these components incorporate the hub seal surface bit. How are you getting around all these hurdles?
"You can not make anything full proof, as the world will simply make a better fool."
(unknown)
I reserve the right to be that fool.
Rohloff hubs and Gate's belt drive are both available from QBP and BTI. All you need is an understanding bike shop that is willing to order the parts for you. Since I am building the frame all manufactures warranties are voided, including Shimano, Sram, Rockshox ect. As a result I take on the responsibility, and the reliability of the design rest only on my shoulders. If it does fail I have no one to blame but myself.
Since I have no intention of starting a buisness, nor do I plan on building this frame for anyone else. I can design this frame for the singular purpose for myself. I choose to build a bike that can not or should not be built, as an intellectual and creative challenge.
The design was done in Solidwork, the analysis was done with Cosmos. I built a test bike with the Gates Belt and Rohloff hub. I've tested an intentional miss alignment and incorrect tension on the belt. With all of this I am confident that this will work.
So where do you get the rear sprocket adapter thing from then? QBP have the gates and rohloff stuff yes, but these won't fit together without some adapter that only rohloff themselves make...and won't sell separately (GGGrrr)...god knows I've tried to get one!
So where do you get the rear sprocket adapter thing from then? QBP have the gates and rohloff stuff yes, but these won't fit together without some adapter that only rohloff themselves make...and won't sell separately (GGGrrr)...god knows I've tried to get one!
If a part can be made by one entity - Rohloff, say - it can be made by another. To paraphrase, overcome and adapt!
Most people ply the Well Trodden Path. A few seek a different way, and leave a Trail behind.
- John Hajny, a.k.a. TrailMaker
Fooly's Major Glory - 650b Titanium Soft Tail, Rohloff/Gates belt drive.
Why belt drive?
It seems to me that it will be problematic because even on hardtails belts seem to be fairly problematic. For a suspended bike the movement in the rear end could cause issues.
Have you tried Cycle Monkey? It seems to me that he is the guy for Rohloff service in the USA and he also sells parts for the Gates belt drive. If you are still having problems you may just have to buy a new hub with the cog already attached. ($$ouch)
I've been riding mountain bikes off and on for the last 20 years. I've been riding the same mountain bike for the last 12 years. I'm getting really tired of the constant chain maintenance. I want this next bike to last another 12 years with out all that chain maintenance and all that shifting issues that go along with the chain. My test bike is almost a year old now, and is now my road bike and daily commuter. Sure it was a pain to set up but I now I just pump up the tires and roll out.
If the belt doesn't work I can always swap out the belt back to a chain. And I can always swap out of the Rohloff for a more traditional chain-gear system. The point is to try the belt and see if I can get it to work for me. This project is all about the journey and not so much about the destination, although the destination is also pretty cool too.
Fooly
PS. Mark I really like your web site. If I wasn't so lazy I would be following in your foot steps.
I'm getting really tired of the constant chain maintenance. I want this next bike to last another 12 years with out all that chain maintenance and all that shifting issues that go along with the chain.
I feel you on the chain maintenance headaches but the past couple of weeks I have been pretty happy with my monster chain. I am running a motorcycle chain on a single speed bike but there is no reason it would not work for belt drive.
My chain is the one on the left
It runs on a special custom chain ring and cog that we made from motorcycle sprockets.
I am hoping it will give me improved chain life so if your belt does not work and you want an extra tough chain think outside the box.
Really? Chain maintenance on a singlespeed? Lube it every two weeks and ride it until it stretches, and replace it with another $35 chain. Seems easier than all the intricacies of belt drive to me.
I have SS drivetrains with plain-jane PC951 chains on them that have lasted years and years, thousands upon thousands of miles, with nothing but the occasional squirt of lube. I don't understand how people have these crazy chain wear problems...motorcycle chain, really?
Occasionally I have a friend come to me with chain problems on their SS and it's inevitably an issue of running a 3/32" cog with a 1/8" track/BMX chain (which they usually bought because it was bigger/burlier looking). If you avoid that, you should be golden for a LONG time.
-Walt
Originally Posted by Francis Buxton
Really? Chain maintenance on a singlespeed? Lube it every two weeks and ride it until it stretches, and replace it with another $35 chain. Seems easier than all the intricacies of belt drive to me.
I have SS drivetrains with plain-jane PC951 chains on them that have lasted years and years, thousands upon thousands of miles, with nothing but the occasional squirt of lube. I don't understand how people have these crazy chain wear problems...motorcycle chain, really?
A chain will last 10,000 years or more if it is not used but I call BS on the millions of miles claim.
The chain above was less then 2k miles using good quality 3/32nd drivetrain parts.
In off road conditions a chain will last at most 2k miles before bad stuff starts happening. With adverse conditions like mud and rain chain life is reduced.
The moto chain is crazy overkill but it is going to last a while. I tend to do around 200 miles a week on my single speed. Most of my riding is off road. Some weeks I do more while other weeks I do less. Chain stretch usually means an adjustment every week or two and end of life after a month or two. The idea with the moto chain was just to have fun and do something a little over the top but it sure rides nice and is perfect for my training bike where I don't care about weight.
p.s. sorry for the thread hijack. It will be fun to see Fooly Major Glory come to life, I think belt drive is interesting but still not so sure it will work on a full suspension bike.
I don't think "thousands upon thousands" is usually understood as "millions". That would be "thousands OF thousands".
Well, YMMV, I guess. I have ridden a lot of singlespeeds a lot of miles over the years, though certainly nothing like your ~30 miles offroad per day average (wow!). If I had to estimate, I'd say the average chain lasts me 4-5k miles (for me, a couple of seasons). At a retail cost of ~$25/chain for a 951, that's peanuts.
But if you're trashing chains every month, I can see why you'd go for something beefier. That is the most riding (you've gotta be doing 30+ hours a week!) I've ever heard of anyone doing on a regular basis who isn't a full-time pro!
-Walt
Originally Posted by febikes
A chain will last 10,000 years or more if it is not used but I call BS on the millions of miles claim.
The chain above was less then 2k miles using good quality 3/32nd drivetrain parts.
In off road conditions a chain will last at most 2k miles before bad stuff starts happening. With adverse conditions like mud and rain chain life is reduced.
The moto chain is crazy overkill but it is going to last a while. I tend to do around 200 miles a week on my single speed. Most of my riding is off road. Some weeks I do more while other weeks I do less. Chain stretch usually means an adjustment every week or two and end of life after a month or two. The idea with the moto chain was just to have fun and do something a little over the top but it sure rides nice and is perfect for my training bike where I don't care about weight.
p.s. sorry for the thread hijack. It will be fun to see Fooly Major Glory come to life, I think belt drive is interesting but still not so sure it will work on a full suspension bike.
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Originally Posted by G-reg
