New MTB: 29 or 650b?

[ChrisV]

About to buy a new MTB and not sure about wheel size. Won't be doing big jumps or anything, but then again you never know! Might like off roading and start tackling bigger trails ...

Anyway, 27.5 seems the way to go, but then there's a lot going for 29 when you read about it. Does it make a massive difference?

 

[Drago]

Depends on the machine and how well sorted the geometry is. I always found the 29er less than ideal for UK conditions, but it's as much a taste thing as a scientific decision.

 

[I like Skol]

Just bought the wife and oldest son a new MTB each, both 27.5s one a size M and the other a size L. I ride a 20yr old 26" and I felt instantly right at home on the 650 wheels. Regardless of frame size both bikes feel planted yet nippy and controllable and they do all the hopping and step bashing that I like with ease and composure. Can't see any reason to go 29r IMO.

 

[MichaelW2]

If you are tall, a 29er
If you are short, a 26"
If you are inbetween, anything.

The industry segments wheel size into style and application, rather than rider size.
eg 26" for downhill, 29er for cross country.

 

[Drago]

Unfortunately, the industry doesn't control the laws of physics, and trying to squeeze 29 inches into a small frame seriously compromises geometry and reduces the mud clearances that are so badly needed in the UK.

 

[T.M.H.N.E.T]

Two geometry specs for a 650b and a 29er respectively. Look closely for the differences (3) then tell me which is which please.

To answer the OP. Test ride all 3 sizes, and 275+ and fatbike then pick the one you like. A bike you like is a bike you will want to ride..

 

[Drago]

Chainstay length is the obvious one.

Other key stats are also missing, most notably trail, and the all important wheelbase. Seeing as the designers have left the head angle the same across both wheel sizes, then by default trail and WB will be bigger, and these are key in determining a bikes characteristics. A big rim with a big trail and longer WB make for ponderous behaviour in a small frame size. Do try and keep up.

 

[T.M.H.N.E.T]

Chainstay length is the obvious one.

Other key stats are also missing, most notably trail, and the all important wheelbase. Seeing as the designers have left the head angle the same across both wheel sizes, then by default trail and WB will be bigger, and these are key in determining a bikes characteristics. A big rim with a big trail and longer WB make for ponderous behaviour in a small frame size. Do try and keep up.

The point you missed (do try and keep up dear chap) is that all this 6ft+ ride a 29 or less than 5ft ride a 275 stuff is pretty much nonsense when the frames do not change considerably as wheel size increases.

 

[Drago]

That's not the point I was making, and never actually stated that. I never suggested small, medium or large riders should go for X, Y or A wheel size. That was Michael W2.

My only observation was that squeezing the big hoops into small frame sizes brings some unpleasant geometry issues, and you very kindly listed a manufacturers figures to prove this point.

Do actually read what people have written instead of trying to attribute options to people that neither hold them or have stated them. Now, try harder next time.

 

[T.M.H.N.E.T]

That's not the point I was making, and never actually stated that. I never suggested small, medium or large riders should go for X, Y or A wheel size. That was Michael W2.

I never said you did, but you seemed to skip the point being made and went on about something else.

My only observation was that squeezing the big hoops into small frame sizes brings some unpleasant geometry issues, and you very kindly listed a manufacturers figures to prove this point.

Unpleasant how? If I ride those bikes back to back, is the one with 435mm chainstay (the whole 5mm longer) going to be worse?? Should I, as Michael suggested ( as someone who is well over 6ft) be riding a 29, when in fact I own two 650b bikes, love them, ride them both and rate them both rather highly.

Do actually read what people have written instead of trying to attribute options to people that neither hold them or have stated them. Now, try harder next time.

Do you?

 

[Crackle]

The small rider 29er stuff is oft repeated hogwash. Like any bike, find one that fits.

 

[Drago]

Take a 29we wheel, with the largest diameter, mass, and gyroscopic forces of the sizes under consideration, inherently the most stable and therefore the least willing to change direction.

The measurements you provided all have the same head angle, so we also have increased trail, acai , another factor which I dressed stability at the expense of flickability.

Then the longer wheelbase also increases stability at the expense of directional ability.

It's the cycling equivalent of taking a graphic equalizer and pushing every slider to the minimum. It's simply far from optimum. You can climb aboard it, you can ride it, it'll work, yet it won't feel the best it could be by the simple expedient of combing several relative extremes of geometry into one machine.

I'm on my 5th 650B bike, and my 2nd 'work' 650B. Do I get a prize, as I'm presuming you mention it as some kind of urinating distance contest? I'm personally not keen on 29ers, and after owning 2 concluded the extra rim diameter was simply extra surface area to collect the claggy clay soil that this area is inflicted.

You ride whatever wheel size you like. If you read back through my posts I have never stated that anyone of any particular height should be considering any particular wheel size, so I don't know why you keep attributing that to me. My contribution to this thread was only to observe sagely that the largest rim size squeezed into the smallest frame size brings geometry compromises that aren't evident with other wheel sizes. I was mentioning FRAME SIZE, not rider size,

If you can find in this thread where I have suggested people of certain statures should have wheels of certain sizes, then quote me. Otherwise, be a good chap and change the record.

So, read back through the thread and QUOTE ME.

Unfortunately, the industry doesn't control the laws of physics, and trying to squeeze 29 inches into a small frame seriously compromises geometry and reduces the mud clearances that are so badly needed in the UK.

See, no mention of rider size, no recommendation that riders of any particular height should be in a wheel of a particular size.

Depends on the machine and how well sorted the geometry is. I always found the 29er less than ideal for UK conditions, but it's as much a taste thing as a scientific decision.

My own admission that is is as much down to ones own prference as any technical reasoning.

Which begs the question. - what are you prattling on about Mr H.A.I.R.N.E.T?

 

[T.M.H.N.E.T]

If you can find in this thread where I have suggested people of certain statures should have wheels of certain sizes, then quote me. Otherwise, be a good chap and change the record.

So, read back through the thread and QUOTE ME.

I've said it twice now but I'll repeat it for you again. I never said you did....

 

[Drago]

Then what are you waffling on about? Christ, you'd start an argument with your own shadow if you were bored.

 

[T.M.H.N.E.T]

Then what are you waffling on about? Christ, you'd start an argument with your own shadow if you were bored.

Have another read, and do try to keep up. My post was in response to Michael re: 29ers suited to tall people.... The geometry says this is not the case as the frames are virtually identical.

I don't know why you're waffling on about rake, angles, flickability and whatever else.