Homebrew 69er

Hi

After reading all this talk about how 29" wheels roll better over roots, etc and my Revs being faulty at the moment, I thought I'd experiment by converting my On-One 853ss to a 69er.

I already had a set of On-One carbon 26" forks so I bought a pair of 29" wheels from on-one and stuck the front one in.

First impressions are that the larger wheel does roll over roots and rocks better. The head angle appears to be pretty similar to a 26" wheel/130mm Rev fork with sag set-up, so it didn't feel at all chopper-ish. I never noticed any problems with sluggish steering through twisty singletrack either.

So far I'm pretty pleased with the way it rides.

Just thought I'd share as I'm sure there has been other folks on here thinking about trying something similar.

Did you have any clearance issues running a 29er wheel in a 26in. fork?

I've been toying with trying out the same myself.

I would imagine hes talking about a rigid fork so it would depend on how long the fork is. I would imagine anything over 430mm + should be ok

You could not fit a 29" in a normal suspension fork.

A 26" rigid fork is the best option for converting a frame set up for 100mm bouncy forks. Clearance is not a problem, I have got a RR 2.4 on at present and there is still at least an inch all round.

No clearance issues with the rigid 26" fork.

Anybody know if I can stretch a 26" tube to fit the 29" rim if I get a puncture or am I going to have to carry 2 tubes.

Cheers.

ive been toying with the idea myself too.
a 26" rigid on one fork + a 29" wheel is roughly the same crown to ground distance a a 105mm fork…. i think. (which is what i have on my XtC at the moment)

maybe ill bother, one day.

Using forks for a 26 wheel with a 29 wheel will give you the wrong trail as the offset should be different for 26 and 29 forks

i did it a couple of years ago, no clearance issues and rear tube fits ok in front

Not really that clued up on the trail / offset thing TJ, but it seemed to feel fine out on the trail.

tempted to give it a bash.
ALL the weight in my SS is in the MXcomp forks.
carbon fork would make it really light 🙂
neowm!

or get an SDinbred frame so i dont have to run a tensioner ^o) but would make it heavier (currently using an Allux frame)
could get a smaller size though to make it chuckier….
hum, decisions decisions.

So long as it felt fine that will do.

Offset is the amount that the axle is infront of the steering axis. Trail is the difference between a line down the steering axis and a line vertically from the axle to the ground.

Using a 29" wheel in a fork with offset for a 26 wheel will give longer trail thus slowing the steering.

This chap uses the terms fork rake for offset which is a bit confusing

http://davesbikeblog.blogspot.com/2007/05/trail-fork-rake-and-little-bit-of.html

ONE ONE did just that with the 456 Ti test bike they gave to one of the mags.. It got rave reviews.

Using forks for a 26 wheel with a 29 wheel will give you the wrong trail as the offset should be different for 26 and 29 forks

True to an extent but not necessarily, depends what frame it's going on really and what kind of fork it was designed for. The concept of 'wrong' trail is not very helpful, I might like my steering a bit more snappy and fast while you prefer a bit more predictable and stable. You are right though that what you generally want for such a conversion (regular xc 26" bike to rigid 69er) is a short rigid fork (suspension corrected 26" fork, say 445mm, with a bit more offset to keep the handling tight and wheel away from your toes on smaller frames. Unfortunately there is only one such fork I know of which is available unless you go custom…

You are just toying with us now Sam. So who makes the "magic" fork?

Using a 29" wheel in a fork with offset for a 26 wheel will give longer trail thus slowing the steering.

Not if it's shorter as this will negate some/all of the effect on the HTA of having the bigger wheel. My Hummingbirds actually have a slightly steeper head angle when using the rigid fork and 29" wheel than they do with a 26" wheel and 100mm fork – coupled with a fork with a bit more offset they have less trail and sharper sterring, which I feel is generally desirable with a rigid fork. It's all about an interplay between original fork length the frame was designed for, head angle, rake, and wheel size – in the end if it feels good then go with it 🙂

The convention is to call it rake when the fork blades are curved, offset when it happens at the crown or dropouts, though the terms to all intents and purposes are interchangeable.

So who makes the "magic" fork?

I do of course 😉 I got a few extra Hummingbird forks made up.

Well I never.

Very sensible of you. I am sure they are at a very reasonable price too.

Oh, but of course – £55 shipped in the UK. Reynolds 520 blades, forward facing dropouts, disc only, green only. Email if interested – website needs updating…

Using forks for a 26 wheel with a 29 wheel will give you the wrong trail as the offset should be different for 26 and 29 forks

Got suspension forks TJ? Don't compress them. Then the trail will be "wrong" as well!

ONE ONE did just that with the 456 Ti test bike they gave to one of the mags.. It got rave reviews.

No – we fitted a Reba 29er fork to a 456 Steel frame. It did get rave reviews (and set me on my way to play with slack head angles more).

My Hummingbirds actually have a slightly steeper head angle when using the rigid fork and 29" wheel than they do with a 26" wheel and 100mm fork – coupled with a fork with a bit more offset they have less trail and sharper sterring, which I feel is generally desirable with a rigid fork.

Also, I've found the gyroscopic stability of a 29er wheel means you can't work on trail/offset/rake alone.

£55 shipped in the UK. Reynolds 520 blades, forward facing dropouts, disc only, green only.

Crazy price. Should be £90. Gorgeous forks Sam. Just lovely.

Also, I've found the gyroscopic stability of a 29er wheel means you can't work on trail/offset/rake alone.

Well, I think it's more that you're just working in a different arena of numbers, the combination of numbers which gives a desired effect with one size wheel won't with the other. You've still only got the same limited variable to play around with though.

Crazy price. Should be £90. Gorgeous forks Sam. Just lovely.

Thanks, and true enough on the price – let's call that 'Sam's STW only crazy special bargain price' – full retail may be more…

I read series of entries on dirtrag.com a year ot so ago about one of the staffers experimenting – successfully – with a 29" front wheel on his Spot. Damned if I can find it – might have been erased like Trotsky's photos following the departures a while back. 😀

I've ordered a pair of Sam's forks, by the way, so if anyone's interested I'll be happy to report back how they work – I'll try them on an old '96 DeKerf and an '07 Genesis Io.

whats the 29er equivalent of a 2.35 highroller? ive got this setup ready to go in the shed, but the WTB doesn't fill me with confidence!

I have a 2.25" Ardent on the back of my 29er and it has been fast rolling and reasonably grippy. Otherwise 2.4" Racing Ralphs are hard to beat IMO.

Can someone tell me the radius of a 29" wheel with something like a 2.25" tyre fitted please ?

Cheers.

wikipedia can…..

Something like 14.25" radius, it seems – good, that'll fit in my 425mm Salsa Cromoto forks then…….

Homebrew 69er from a few months ago

http://www.singletrackworld.com/forum/topic/how-would-your-tyre-hit-your-crown

Right, the forks arrived today from Sam, and a cheapo 29er front wheel turned up about 20 minutes later. I'll get the crown race pressed on tomorrow when the shop's open and buy a tyre and tube, and report back.
Incidentally, I looked at the geometry for both the small size Hummingbird and the 16" Io, and, aside from a .5 degree change in the head angle and a 10mm difference in headtube, the numbers are strikingly similar.

No idea what tyre to go for, but liking Maxxis advantages a lot at the moment, so may see what's in stock at the local shop…

Hi Sam, okay if I get one of these forks at that price via my LBS (Singular partner store)? I have a wee bit of credit :¬)

bent_udder, I've got a brand new Kenda Nevegal 29×2.20 dtc tyre on ebay at the moment if your interested. To you I'll do it for £20 posted.

Kenda Nevegal 29×2.20

Cheers Sqwubbsy, but I owe my local bike shop some love, so I'll see what they've got first, if that's OK.

Nae bother.

Special offer all over, well done to the few who got them at that price. Full retail is £75 plus shipping.

following the on-one style pricing policy i see.

Wouldn't the on-one policy be introduce at 55, bump up to 75 for a while, drop back to 32, hike up to 140, etc etc

OK, steerer cut, tyre and tube bought, everything assembled. First ride tonight was smashing. It handles like a 'normal' bike with no flop. Main issue is dealing with the disparity between small and big wheels, a little tricky on a singlespeed. I almost stuck my nuts in the stem on a climb earlier, as the front wheel rolled over a root and the back one hooked up. Oops.

Other than that, very nice. Not much gnarl on Leith tonight (I went past, but not over, deliverance), but the feel is somewhere between my normal Rebas + 26" wheel and a P2 + 26" – the bigger wheel definitely absorbs a lot of stuff it wouldn't otherwise. A tiny bit of wrist buzz, mostly due to me trying to pump the bike into corners a bit too hard – too many years on bikes with suspension forks, mostly 😉