26" Wheels on a 29er. Daft idea?

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mrjemm
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26" Wheels on a 29er. Daft idea?

Postby mrjemm » 18 Dec 2012, 9:13pm

Purely academic question here. Unless I get really tempted by answers.

Would this work? I don't know about bike geometry really, so it's probably all down to some little number I have no clue of, but having been looking at various mountain bikes for touring purposes, I've got distracted by some newer models that look very nice. And this got me thinking- would putting 26" wheels into a 29er frame be feasible?

How my mind is working here, is that if not wanting to do mountainous stuff, a high bb isn't so important, and I am guessing that a 29er frame would have a bb set set lower relative to hubs than a '26er' because the extra wheel radius allows it. At the same time, chainstays will by necessity, be longer, and toe to hub distance (clearance on a 26er) will be greater. Also, because both wheels are the same size, all angles should be the same, no?

I know there are benefits to both size of wheel, and that's been discussed in other threads, so I can follow those discussions elsewhere. I have seen mention of 26" wheels being used in a 29/700c frame (see bumper's post here- viewtopic.php?f=15&t=3832&p=279758&hilit=peregrine#p279758 ), but never a discussion of it.

I also am aware of models where both are available as an option (Surly's Truckers for example), but they have different frames.

One that interests me is the Genesis Fortitude Adventure, which uses relatively short rigid forks apparently.
http://www.genesisbikes.co.uk/bikes/fra ... -adventure

Whaddya reckon, a daft idea?

Cheers, Jem.

mrjemm
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Re: 26" Wheels on a 29er. Daft idea?

Postby mrjemm » 18 Dec 2012, 10:48pm

So, maybe this is such a daft idea. Or I posted it late. Or in the wrong place- after all, this is a quiet forum and maybe this shoulda been for bikes'n bits. Ah well.

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RickH
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Re: 26" Wheels on a 29er. Daft idea?

Postby RickH » 18 Dec 2012, 11:22pm

This page about the Kinesis Decade Tripster says:-
The Tripster... can be built in a number of different ways to exactly suit the riding style of the individual. Use it with 700c wheels, road tyres and drops or 26” with road tyres [we recommend 1.5 minimum, 1.9 max. to keep the BB height up] and flats, or with 29er wheels and flats, or set it up with 33x700c ‘cross tyres as a weekend racer or real on/off road commuter.

If that helps.

Rick.

Brucey
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Re: 26" Wheels on a 29er. Daft idea?

Postby Brucey » 19 Dec 2012, 8:53am

I'm sure it will 'work' but whether it will do exactly what you want, or be the best way of acheiving your objectives is another matter.

I agree with the logic re the BB height and chainstay length, but you would need to check all the details. One concern I have about all 29ers is that in small sizes, (especially by the time you have enough room for a supsension fork....) the head tube ends up being very short, and the top tube can be rather long.

I would imagine that by the time you have confirmed all the details, you might well be an expert on geometry.... :wink:

cheers
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BeeKeeper
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Re: 26" Wheels on a 29er. Daft idea?

Postby BeeKeeper » 19 Dec 2012, 10:19am

I don't think the low BB is the issue on roads, but the pedals would be a bit closer to the ground which might prove a problem at times although the difference between the two wheels is not that great I think. I have just measured the wheels on my Surly Ogre and the external diameter of the wheel fitted with a 42mm tyre was 27.5" and measuring a 26" wheel with 2" tyres the external diameter was indeed 26". Not an exact comparison as the bikes have very different tyres but on that basis you might expect the pedals to be between 1" and 0.75" closer to the ground, depending on what tyres were fitted to each wheel.

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al_yrpal
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Re: 26" Wheels on a 29er. Daft idea?

Postby al_yrpal » 19 Dec 2012, 11:48am

On a Mtb you are always looking ahead for roots, stumps and rocks because you can hit your pedal and easily get thrown off. Anything that makes that situation worse should be avoided like the plague. Yes, a daft idea...

Al
Touring on a bicycle is a great way to explore and appreciate the countryside and towns you pass through. What do you do to make a difference?

mrjemm
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Re: 26" Wheels on a 29er. Daft idea?

Postby mrjemm » 19 Dec 2012, 12:58pm

Thanks guys.

I'll have a look at that link RickH, cheers.

As I was saying, it's really just academic; only perhaps potential of becoming reality would be if your answers bedazzled me and I suddenly got an unexpected Xmas bonus!

Al (and Beek) I think you may have got the wrong end of the crank-stick- I am thinking that a lower bb could be a good thing; this is 'blue-sky thinking' (powerpoint bingo!) coming from an investigation into using an MTB frame for touring, not mountain biking. For anything away from MTBing, I think a normal one has too high a BB often, so I was wondering if this was a way of getting it lower proportionally, and increasing spacing at the ends (luggage and toes).

Beek, I would only think about using a standard length crank, so the pedal would only be as proportionally low as the bb- it's not that I'm thinking about bb clearance, but the other way around! Like I said to Al, this isn't about MTBing, so I am not thinking the ground clearance (pedal or bb) is so important. Seems like the sizing of 29er is not 29" though, if your measurements aren't bonkers. Weird.

Brucey, you seem to have hit the biggest hurdle of course- top tube. Looking at the figures for that rather nice Genesis, the TT is long. Pretty damn long.

Have realised this morning though, the Vaya is referred to as a 29er in places, so I should simply give it a go! Still like to give the Fortitude a go though.

Thanks once again.

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al_yrpal
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Re: 26" Wheels on a 29er. Daft idea?

Postby al_yrpal » 19 Dec 2012, 1:49pm

Before I got my Vaya I contacted Salsa Cycles to see whether I could fit my existing 26" wheels to a Vaya frame, here is their answer...
Hey Alan,

Sorry to say that won’t work. Those bikes were designed from the ground-up to be used with 700c wheels, so sticking a 26” on is going to cause many problems, from handling to your pedals hitting the ground.

You could always have your old wheels re-rimmed with 700c wheels…they really are great bikes.


Al
Touring on a bicycle is a great way to explore and appreciate the countryside and towns you pass through. What do you do to make a difference?

mrjemm
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Re: 26" Wheels on a 29er. Daft idea?

Postby mrjemm » 19 Dec 2012, 2:09pm

Cheers Al, that's interesting to read. I wonder if that's the case for most 29ers. The Vaya is a more road orientated bike of course, with a fairly standard BB height. I think I may give it an experiment though- perhaps that should be away from the public highway though!

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RickH
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Re: 26" Wheels on a 29er. Daft idea?

Postby RickH » 19 Dec 2012, 5:19pm

Just remembered that sometime back I emailed Genesis about the possibility of using 26" wheels in a Croix de Fer frame - primarily because I have some 47-559 Schwalbe Winter Marathons & was thinking about whether it would be feasible to use those for winter and/or use fat MTB tyres for rough stuff type riding. Their reply was as follows

Genesis wrote:Interesting questions & one which I've not encountered.

The distance between the insides of the fork legs at the approximate point at which the tyres would be at their widest is 58mm.

Worth also considering that by running 26" wheels you'd be lowering the BB - ground clearance, and the turn in will feel much twitchier with the smaller diameter wheel/tyre combo.

Because it's not designed for 26" wheels in mind I wouldn't like to stick my neck on the line and commit to a size or recommend that it be tried, so it'll be very much experimental (but we'd love to see what you create if you do go ahead).


So a bit less negative :D

Rick

mrjemm
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Re: 26" Wheels on a 29er. Daft idea?

Postby mrjemm » 19 Dec 2012, 6:54pm

Indeed. That's good to read.

I'd be interested to know more about bumper's (see my 1st post) set up. Seems he was in here the other day. Maybe I'll go look at his linked site/blog...

Edit. Awww, it's gone.

bumper
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Re: 26" Wheels on a 29er. Daft idea?

Postby bumper » 19 Dec 2012, 7:14pm

Jem,

Unless you've got a frame with an eccentric bb I would advise against it. My peregrine had one so I could adjust the pedal/floor height.

I used 26" wheels because they were a nice dt Swiss on xt hubs pair that I didn't want hanging in the shed, secondly 26" tyres are much more readily available (at the time anyway) and I could always get spares wherever I was in the country.

The bike is now in Scotland somewhere and still with 26" rims.


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mrjemm
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Re: 26" Wheels on a 29er. Daft idea?

Postby mrjemm » 19 Dec 2012, 7:36pm

Thanks for that reply bumper. Interesting answer.

D you think the handling normal, or perhaps adversely affected?

bumper
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Re: 26" Wheels on a 29er. Daft idea?

Postby bumper » 19 Dec 2012, 8:03pm

The handling was brilliant. The wheels didn't feel odd at all, it was very responsive with the 26" fitted.

Why don't you try to get an older mtb steel frame and fit drops? It will be canti or v brake but it will cost less than buying a 29er frame, fitting 26" and then deciding you don't like it.


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mrjemm
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Re: 26" Wheels on a 29er. Daft idea?

Postby mrjemm » 19 Dec 2012, 8:34pm

Ha, I have an older steel mtb project on the go at the mo, and a 2nd impending. Unlikely to put drops on though- just taken them off my Vaya 'tourer' (jack of all) as it is.

Not so far from what I recently did to my old alu malt though, but with upside-down moustaches... (seat down as madame has now claimed it).

ChocMalt1sm.jpg


Glad to hear the 26" Peregrine was good to ride. But this is likely to remain academic, at least for now.