Cool project, would like to see pictures :)
So we are still working on the development of this bike.
Marcel at Nicolai worked on an initial view of the geometry which looked like this. This geometry still has 454mm chainstays.
The main problem is the clearance to the seat tube with 145mm or more of travel whilst maintaining the kinematics of the Ion 16, which is a key feature of what we are trying to achieve and the Eccentric Trail Key or ET.
We have been discussing the desired/most important attributes a lot between myself and Dipper, I think we have concluded that the major opportunity here is to:
- Improve the agility over our custom AC 29er bike by trying to use shorter CS than the 454mm we have
- Be able to run a big rear tyre (Schwalbe HansDampf or Ardent 2.4) whilst keeping at least 145mm of travel
- Ensure the BB is right for the tyres intended, so assuming 745mm diameter, thus keeping CofG low and keeping the stability.
-Keep the front as low as possible using ZS headset. .
-Retain the features of Ion features so the suspension action (kinematics of the Ion 16 26" with the progressive to linear rear linkage), weight, post mount brake, improved bearings etc
You can see in these drawings how in the low setting, at the moment with 145mm of travel the clearance is too small between the tyre and ST based on a 750mm Diameter Ardent.
So more work has been done on the design now around the BB, kinematics, clearances etc This has resulted in most of the wants being fulfilled :D
The latest drawing is here.
This shows that we can achieve 450mm CS and fit the big tyres, with enough clearance to the ST, with a suitably wide rim :thumbsup:
The HD and Ardent have been measured on Enve AM carbon and NoTubes Flow rims. The new Flow is 1mm or so wider internally than the AM carbon so will give a very similar overall diameter.
Wheelbase is the same as my current custom AC with the same HA but with shorter CS.
BB heights look good.
I have some concerns over the steepness of the ST in 'high' or normal trail mode and we have only 0.5deg difference between low and high mode on the head angle.
I have no experience of a ST angle that steep or what that does to a pedalling position. I guess it can be resolved by having the saddle slightly further back. My current AC has a 74deg ST angle.
I think we need to give consideration to bringing the ST angle back to 74.5deg in the high mode and accepting that the low mode is perhaps not necessary. Its clear that 74.5deg gives enough clearance to the tyre as that is the seat angle in the low mode now.
If a slacker head angle is desirable, switching out the headset to a -0.5 or -1deg ZS works components headset may be a better solution, for example if you're riding whistler and want to run with 66deg then that can be done with only a 2mm drop in BB and 10mm increase in wheelbase, that gives a pretty short rear end compared to front centre.
On a personal note, I am considering if a 10mm shorter ETT would work for me as I am now running an 800mm wide bar, but given what we are trying to do that is just noise!
You can see the linkage curves here too. The linkage ratio curve is similar now to the Ion 16 26", obviously with less travel so with a lower overall raito, the curve is slightly less progressive from mid to end stroke than the 26" (a little more linear, but not much.
This is a very different ratio curve to the AC custom I have which is regresive initally in the sag zone but then very progressive for the remainder of the travel.
So, we can get to 450mm CS and keep the kinematics of the Ion16 :thumbsup:
Some further thought on the ST angle, would 75deg be ok and how important the ET key is (In terms of being able to use it)
I must say I'm pretty stoked about it at this point:D
That looks very, very nice.
I might be interested in one, once you got it ripe for production.
160mm fork compatibility would be a killer feature for me! Not many 29ers do that yet, but it will be the future.
I wouldn't worry about a 75 degree ST angle.
Look at the Rocky Mountain full suspension bikes, it works.
Once sagged a very steep seat tube angle keeps the riding position efficient.
If you desire a more classic position you can just slide the seat back or go with a setback seat post.
I'll follow this project really carefully, might just be my next bike. Absolutely what I am looking for.
My current Stumpjumper FSR 29er is very nice. Can't imagine to go back to a 26er, because of my really long legs. But the 130mm Stumpjumper and fork are just not as burly as the FOX 36 or Lyrik equipped bikes I rode before.
The Stumpjumper actually blows them away on the descents, but I just want a bit more.
Now I'm itching to see this frame whilst it's still hot off the tig table... :D
Me too. I wasn't in a hurry before but Now I just want it built! Hopefully we'll make the next production run so its here springtime'ish
I spent sometime today discussing the design with Marcel at Nicolai, it was very productive to have the dialogue.I proposed some changes and posed some questions last week based upon the post and concerns identified above and Marcel had been looking at the design based on those proposals. I think we have got what we were aiming for :thumbsup::D
The seat tube is now 74.5deg in 'high mode' and 75deg in 'low' mode, using a slightly larger offset at the BB.
The BB pivot is optimised for pedalling with a 28-32T front chainring and should perform very well when out of the saddle.
Travel remains at 145mm, but we have lifted the BB height to 340mm in high/333mm in low, with 2.4 tyres front and rear (745mm diameter Ardent or HD) and the rear stays are 450mm or 17.6". I am confident from experience this will feel good but also keep pedal strike at bay with 145mm rear travel.
The linkage curve remains as above for the Ion 29. Its the same linkage arm as the 26" Ion16 and its this, with the revised packaging, that results in the ET key changing the HA by 0.5 deg rather than 1 full deg and the slightly less progressive curve towards the end of the travel.
Alot of testing was done with the Ion16 and the CCDB air with a HV chamber was found to be a great match. This revised curve looks like it would suit a CCDB air with a LV chamber and work really well.
The head tube is kept to 120mm keeping the stack down.
The revised drawing will pull in the ETT to 605mm for me (with 800mm bars) , I think Dipper will keep 610mm. Whafe may well go to 620mm?
I imagined keeping the 67/66.5 head angles, but I'm just thinking about the fact that we have mismatched travel, 150mm/145mm or possibly 160mm/145mm F&R respectively so will incur between 1.5mm and 4.5mm of additional front sag, its only .08 to .2deg but I wonder whether to change the angles to allow for it, maybe 66.9/66.4...maybe that's a bit too anal given all of the other variables on the trail! (
So, just waiting for what will hopefully be the final drawing of the frame with my dimensions, then get Dipper and Whafe's dimensions/angles (I'm thinking ST length/ETT/HA as the rest of the design should be sorted now, though I'd suggest staying with the 67/66.5 based on my experience) dialled in too.
Sounds awesome! :thumbsup: What body parts do I need to sell to get on the proto-type queue? ;)
I think "mis-matched" travel is the way to go with FS 29ers... and this "Ion 15 29er" looks to be the ticket. With a 160mm fork, I get shudders just thinking about it. Might need to add a drag-chute to my CamelBak!
The geometry looks dialled, though I usually ride a "medium", so would prefer an ETT of ~595mm, a headtube between 100mm~110mm, and seattube of ~440mm for some crown-jewels clearance! :p:eek:
StanleyJ, I ride a medium in terms of the crown jewels and I'm only 5'11|", 470mm is the same ST as a Med Helius AM but I found the med too short at 595mm with a 50mm stem and 800mm bar, I needed a big layback seatpost which affected handling. The top tube finished 70mm lower than the ST height on this bike. It could be made shorter tho.
I think 120mm is as short as we can go on the HT too. Some fairly chunky tubes to be welded on and Nicolai don't do bends period;) let alone just to make the TT and DT come together more closely and provide clearance!
I'm in two minds about the 160mm fork. I like the idea of the travel but the potential weight bothers me. My current bike, the Custom AC29 comes in at 28.5lbs with big tyres and pedals but the Fox F34 Float 29 and I am hoping to bring this one in around the same if the relationship between production AM29 and Helius AM to Ion16 remains. so I suspect a weight of around 3.3kg, which will be great.
Hmmm, I'm a full 2~3 inches shorter than you, and the only vaguely similar bike in the stable is Canfield Yelli, in a medium with a Fox F34 Talas and 55mm stem/710mm bars. The ETT there is ~605mm, fairly slack seat-tube angle though. However being a reformed roadie, which in turn was a reformed BMXer, used to riding bikes that are short (BMXes!) though also prefer to be more stretched out on a bike (road bike!). The Yelli weighs in at 28lbs, so I personally wouldn't loose much sleep over the fact an FS 29er is "a touch" heavier.
Originally Posted by the_pilot
Shoulders are not wide enough for 800mm bars, though 750ish-mm might work. I would think a 50mm stem would work for me, so maybe a slightly longer ETT on this "Ion 15 29er", dead on 600mm or perhaps a touch longer. I think a 610mm ETT, I'd be venturing into sub-40mm stems!
And to be fair, the headtube is Zero-stack, so having it a fairly "long" 120mm probably is a non-issue. I would still prefer to have a 150mm fork on it rather than "just" 140mm. As for a 160mm fork, that's just vapourware at this moment and it'll depends on which chassis Fox/Rockshox/whoever make such a fork with. Just here on other forums of MTBR, quite a few people would at least like to see a 160mm Fox 36 29er... :eek:
Actually my mistake, I only ran a 760mm bar on the Med AM,
This bike is definitely for a 150mm fork Stanley and I agree the 160mm is in the ether right now so designed to take it that's one thing, but I don't think it should be designed around it, definitely not for me.
But making this ETT shorter should be no big deal if you wanted one, The ETT needs to be right for you and your bars, its custom after all!
And why does this thread keep not showing the files I've attached!!!
760mm bars makes more sense! As for fork, it's always the rule of thumb +20mm is usually okay, though with how long, longer travel 29er forks are, seems the new-rule-of-thumb is +/-10mm. So in this case, 140mm~160mm, with the design being for 150mm. Now if only Fox will make those 150mm F34s available on the retail channel... :madman:
As for ETT sizing, I know I can get exactly what I want if I go custom... though just going by what the standard sizes where, seems I'm right between a medium and a large, so just talking to myself out loud I'd go down a size rather than up, considering how I'd prefer the bike for its intended application. :thumbsup:
For the images you're trying to upload, tried posting them inline using the [ATTACH]attachmentid[/ATTACH]?
Testing... (just a Helius AC 29er!), using http://forums.mtbr.com/attachment.ph...1&d=1359252418
Edit: Weird... it is only loading intermittently. :rolleyes:
Okay, just got the revised drawing from Marcel
This incorporates all of the changes we have asked for packaged in a way I think will work fantastically well. The plan is to keep this design around the 150mm fork a2c but with a down tube that will take up to 160mm...just in case, it will add between 50g and 100g, so one less sausage before a ride;)
You can see that we have got the stack down a little and reduced the wheelbase down to 1180mm with 4mm less reach and the shorter CS but with 67deg HA in the high position. In low it will be 66.5deg and approx 1185mm which is 10mm shorter overall than my current AC29 custom.
I have the go ahead to go to Hoshi for some new graphics, the plan being to base them on those designed for the Ion16 team bike over a raw frame.
I think we should just call it the Ion29. I can't imagine, at this, time any evolutions. I do think this is as long a travel as you would build a 29 as an AM bike.
Unfortunately, it turns out demand for the Ion16 has been really big, so we will be looking at a delivery wk 21 unless a second Ion16 batch run is required in which case they can be built at the end of that and could be a few weeks earlier.
I'm waiting for a few photo's of the design process...for now it will have to do, can't wait now!!
Hmmm, given the "Ion 29er" is designed around a 150mm fork and strong enough for a 160mm... what's the current situation in actually being able to get such a fork in 2013? It would be ace if Rockshox, Fox or anyone else actually offering these at retail level... otherwise, would/could/should Nicolai offer such a fork with the frame as a "chassis"? Exactly like what Niner do with the UFO?
I thought I'd replied to this one StanleyJ. iphone fail!
The Fox F34 Float 29 is available retail, at 150mm if you request it when you order. Certainly in the UK, Mojo will do this.. All 2013 model Fox F34 Float29 can be converted simply with a couple of parts if you already have one.
More than one industry source has told me that there will be a 571mm A2C crown 29er fork available this next model year from RS, so that's a 160mm fork.
Orders are in! Wk 21 delivery in theory..
160mm forks are definitely coming. There is at least one other 160mm compatible frame design in the works I know of...
A Specialized or a Santa Cruz 160mm 29er?
No, nothing so mainstream. And only long fork compatible, not long travel rear. And only a proto. OnOne Codeine. Short travel rear, sub 130mm, but up to 160mm forks. (Sorry its brief, don't want to derail this thread!)
Hard at work designing & refining the Ion29 in Lübbrechtsen..
Exciting stuff, pilot, your work on this project has been outstanding and appreciated...
Will pull the trigger at some stage. Will be the perfect bike in my opinion. The AM 29er of mine is not really the ideal bike for am and trail, it is great, but not perfect. I am for sure used to the big fork and used to the weight, but to have a trail gobbling lighter 150mm strong fork would be awesome.
Mmmmmm, the mind boggles
Have been off the pace with MTB of late having done a half ironman, but am getting really hungry for it again.... Been on the Cevelo S5 heaps of late... Road ride today and a MTB in the morning for me.......
Thanks Whafe. Kind words. I can't wait now. What with this bike, XX1/bling ring 1x setups with clutch mechs, and Maxxis announing a 29er 2.5 minion front and a 2.35 high roller 2 things are looking good.
ooh! a 2.5 minion! will we have enough room for one o them in the back?! ;)
Originally Posted by the_pilot
roll on the welding pics. then we'll know its close!
what weight will this beast come in at ?
XX1 drivetrain but what fork is proposed ?
I'm probably not going to run XX1 initially until Chris King makes a compatible free-hub.
In the meantime I am already running a Sram X0 crank with a 28t, sometimes 30t blingring from MRP with 11-36 XX rear cassette and XT clutch mech. So I get close to the gearing (and its fine for me even in Bonnie Scotland) at the bottom but not quite the top end. I'm not bothered about the top end there as by that time I'm not pedalling!
When they bring a mech out for less than £240 rather than £50 XT clutch I'll think about it!
As for forks. The minimum is 150mm 562mm a2c and the plan is for a Fox F34 float29 150mm.
Rockshox are bringing out a 160mm 29er fork this year with 571mm a2c.
I worry it might be heavier than I would like. The Fox is the same weight as the 140.
Target weight, based on my current AC/AM running gear and assuming that the weight relationship is similar between the two 29s as it is between the Helius AM and Ion16 i.e a 3.3kg frame or less, is 29lbs with the extra weight of a CCDB air (300g heavier than RP23 CTD) but the linkage curve on the Ion is less forgiving for air shocks at the end of the stroke but there is plenty if adjustment of the CCDB to make sure it's kept under control (So Marcel tells me based on their setup of the Ion16)
oh the waiting...
We are discussing some decal options at the moment to keep the hunger at bay...