29er Exotic Forks on 26'' Frame and Wheel.

[worzelrummage]

So my new frame hunt looks like it going to end up with what I originally wanted. On-One Evo 2.

My question is, the frame is designed for long travel forks, however, I love the look and direct control of rigids and and especially carbon forks. The bike is going to be used as my 'do it all bike', commuting, long xc rides, touring, summer razz's about city, you get it everything!

Now to make up with the loss of travel is the anything fundamentally wrong with using 29er forks. Is this going to chuck my geo out and feel horrible?

I think the 29er version on the fork is the equivalent of 130mm travel.

Is this a good idea or should I just stick with suspension?

 

[Kult Friction]

Re:

Should be fine, as long as you stay within the limits of the recommended A-C, It'll just be a 69er.

I've a Singular Hummingbird which is exactly that, the bike can either be run 26/26 with a 100mm fork, or 26/29 with the Singular rigid fork.

 

[hamster]

I think it makes complete sense for a commuter / tourer. The only thing I'm not sure about is the fork offset which I imagine should be different for a 29er as the wheel diameter is larger.

I have a set of 26" carbon disc forks at the 440-460 sort of size if any use. The steerer is good and long too. I'm away with work, drop me a line if interested on Thurs..

 

[worzelrummage]

Interested but lost at the 440-460 size?

 

[mechanical_vandal]

Interested but lost at the 440-460 size?

Axle to crown measurement of the fork. Find out what a2c measuerment the frame is designed for and find a rigid fork with similar a2c.

A2C is a much better way to measure a fork than travel as a two different models never mind brands of 100mm travel fork could have a2cs that differ by 20, 30 even 40 or 50mm.

I've also ran a 29er fork and 29+ wheel/tyre on a bike designed for 26" wheels and a long travel fork. I found it made for a bike that was great for technical descents.

 

[worzelrummage]

Thanks for clearing that up, makes perfect sense.

Is there a way apart from emailing the company to find out what a2c fork the frame is designed for, as most companies only give a recommended travel size.

For example, a Dialled PA is recommended 120-140mm travel. Now looking through this http://forums.mtbr.com/shocks-suspensio ... 70024.html
That includes a massive amount of different a2c measurements.

 

[N/B]

Hang on a sec... were you intending to chuck a 26" wheel into this 29er fork?

 

[Osella]

Re:

Funnily enough, you'll probably get a different answer from On-One compared to anyone else anyway!
Brant (designer of such frames, plus Ragleys) designs frames around the 'sagged' a2c measurement of a fork, so his a2c geometry is different to that of many other frame designers who base their geometry around an un-sagged fork (so the angles become steeper as the rider gets on the bike and the fork 'sags' a little into its travel.)

It's all notional anyway though, as mentioned above..but what you can infer is that any On-One frame will be designed for a slightly shorter a2c than the fork's static measurements. In the case of a 456 Evo 2, the clue is in the name, as it's named for it's travel range of 4/5/6 inches (min-max). If you take a Rockshox fork as a 'standard' (Pikes are usually common) then you're looking at a sagged geometry based between 80mm and 130mm of travel (20mm sag), so 462-498mm a2c (approx!) where a Duke/SID is 425 sagged.

The 26" version of the Exotic forks is 445mm a2c for reference, all within the range that the frame was designed for, even if the 29er versions are 498mm.
The 445mm a2c versions of the Exotic forks will fit any wheel size up to 29er (excl 29+/Fat) anyway though; so might be a better bet if you're thinking of running both wheel sizes on the same frame as you won't be jacking up the BB height - which you will do if you have a higher a2c fork and that might completely throw out the handling..

 

[stevet1]

Re:

FWIW - I'm about to do something similar. Tonight I will be fitting a 29'er fork (Surly Karate Monkey) onto a bike running 26" wheels front and rear. As you say, it's difficult to get rigid forks in 26" flavour that match the A-C length of longer travel forks.
I checked the offset, and the 29'er version of this fork is 43mm vs. 40mm for the equivalent 26'er fork. I decided any difference would be negligible.

 

[Dickyboy]

Re:

I ran a Prince Albert with Salsa Cromoto 29er forks & 26" wheels was great.