67ers & 79ers the next big thing? - discuss

EdW

By 67er I mean 26 rear wheel & 27.5 (650b) front.
And a 79er is 27.5 rear & 29 front.

Whenever I read anything related to the wheel size debate, the arguments for & against bigger wheels seem to be:
Pros: faster rolling, roll over obstacles better, better cornering grip.
Cons: sluggish acceleration & cornering, longer chain stays, heavier/flexier wheels.

It seems to me that most of the pros are related to the front wheel & most of the cons could be solved by a smaller rear wheel.

So, I think the ultimate XC/trail bike (up to about 130mm travel) should be a 79er & the ultimate (longer travel) AM/enduro bike should be a 67er.

I know Liteville's new frames can use this concept, and some DH bikes have used 24” rear wheels. So not a new idea, but now that we have 3 common wheel sizes to choose from, such combinations are viable.

I assume it wouldn't be as simple as, for example, just putting a 650b fork & front wheel on a 26” frame – some geometry adjustments would probably be required for optimal performance.

lawman

No. Just no.

kajjal

Just by a chopper or tomahawk and be done with it

Kowalski675

Liteville are already doing it this year. The smallest size gets 24" rear/26" front, then 26/27.5 followed by 27.5/29 with 29/29 on the largest. Is there no end to the wheel sze fannying about, lol...

rockmonkeysc

I had a Honda Fireblade with a 16" front wheel and 17" rear. Twitchy bastard.

EdW

I guess what I'm really saying is that now the industry has lumbered us with 3 different wheel sizes, we may as well fully exploit the benefits that each size can bring.
In my opinion that means putting a bigger wheel on the front & smaller one on the back.

Also my solution simplifies things as there will only be 2 sizes (67er & 79er) instead of the current 3 (26", 650b & 29er)

Kowalski675

RockmonkeySC wrote:

I had a Honda Fireblade with a 16" front wheel and 17" rear. Twitchy bastard.

But the 130/70 16 tyre made it virtually the same size as a 17" rim with 120/70 17 anyway (the difference is about the same as the difference in radius between a new front tyre and a worn one). Yes, early 'Blades were a little flighty, but not to anything like the extent that people remember them as being, and it wasn't down to the front wheel (which was as much of a marketing gimmick as the holes in the top fairing). They were a positive paragon of stability compared to plenty of other bikes. My RG250 had a 16" front and 18" rear, that was twitchier than any Fireblade, lol. My 2010 Street R has sharper geometry than an early 'Blade (shorter wheelbase, less trail, steeper rake) with less weight and a higher power to weight ratio. A 2004 ZX10 makes an early Blade look as stable as Ayers Rock

Kowalski675

EdW wrote:

I guess what I'm really saying is that now the industry has lumbered us with 3 different wheel sizes, k:

It hasn't really though, has it. The industry's basically abandonded 26" already.

lawman

How is it a solution though? What benefits would a bigger front/smaller rear wheel bring? If anything I'd say it complicates things further. I've ridden a bike and thought, "you know what I wish this bike had a bigger front wheel". Trek tried it with a 29/26 and it flopped. There's a reason it hasn't caught on already.

Kowalski675

I believe Specialized have dabbled with it in the past too?

lawman

They did with the Big Hit, but that was back in 2003/4 when everyone was throwing themselves off cliffs Josh Bender style and fitting 300mm travel forks and 24" wheels were considered stronger, and seeing as everyone landed back wheel first, Spesh thought they'd try 26/24"... Needless to say they realised the error of there ways and haven't done anything as stupid since.

Kowalski675

That's before my time in MTB terms (all my hooliganism then involved an engine between the two wheels), and I have no idea who Josh Bender is, but I imagine he got a hard time at school with a name like that.

EdW

lawman wrote:

How is it a solution though? What benefits would a bigger front/smaller rear wheel bring? If anything I'd say it complicates things further. I've ridden a bike and thought, "you know what I wish this bike had a bigger front wheel". Trek tried it with a 29/26 and it flopped. There's a reason it hasn't caught on already.

I had heard about the Trek "69er" & a quick google search shows that Bikeradar gave it 4 stars, maybe it was just ahead of it's time, or a 3" difference in size is too much.
I bet people riding 650b or 29ers wish they had smaller back wheels though, so they can keep the bikes fast rolling nature, but have better acceleration, sharper handling & better climbing ability because of the shorter chainstays.

lawman

EdW wrote:

lawman wrote:

How is it a solution though? What benefits would a bigger front/smaller rear wheel bring? If anything I'd say it complicates things further. I've ridden a bike and thought, "you know what I wish this bike had a bigger front wheel". Trek tried it with a 29/26 and it flopped. There's a reason it hasn't caught on already.

I had heard about the Trek "69er" & a quick google search shows that Bikeradar gave it 4 stars, maybe it was just ahead of it's time, or a 3" difference in size is too much.
I bet people riding 650b or 29ers wish they had smaller back wheels though, so they can keep the bikes fast rolling nature, but have better acceleration, sharper handling & better climbing ability because of the shorter chainstays.

But when 650b bikes can have shorter chainstays than a 26" bike, what's the point? Like wise for having a 29er with shorter chainstays than a 650b bike. It just creates hassle as has been said already. I think if you're going to have the benefits of a given wheelsize then go all the way. There's so much more to bike design than just the wheelsize, how many times does it have to be said?! :roll:

supersonic

If I was going to have double wheel size (on a HT), the larger wheel would be on the back.

But I'd rather stick with my 26ers that I have.

Hob Nob

EdW wrote:

I bet people riding 650b or 29ers wish they had smaller back wheels though, so they can keep the bikes fast rolling nature, but have better acceleration, sharper handling & better climbing ability because of the shorter chainstays.

There are more & more of 29" bikes in the AM catagory with chainstays shorter than the majority of 26" bikes.

EdW

Hob Nob wrote:

EdW wrote:

I bet people riding 650b or 29ers wish they had smaller back wheels though, so they can keep the bikes fast rolling nature, but have better acceleration, sharper handling & better climbing ability because of the shorter chainstays.

There are more & more of 29" bikes in the AM catagory with chainstays shorter than the majority of 26" bikes.

And to achieve that they have compromised the design of the frame in other areas in an attempt to mimic the characterists of a smaller wheel. I'm saying if they just use a smaller wheel they might be able to avoid the compromise.

lawman

What compromises? Specialized designed the Enduro 29 with shorter chainstays than most 26" bikes, yet you can still fit a front mech if you want too. Where is the compromise in that?

EdW

The Enduro 29 is compromised in comparison to a 26" Enduro in that it's chainstays are longer, 10mm less travel, the pivots/linkages positioning may not be in the optimal position, the wheel itself will be either heavier, flexier or more expensive.
I am suggesting that a mixed wheel size Enduro would be better than both the 26 & 29 versions.

The Rookie

[quote="EdW"
I am suggesting that a mixed wheel size Enduro Could be better than both the 26 & 29 versions.[/quote]
FTFY

lawman

Well done, you've arrived at the point where 650b comes into play. The clichéd view is that 650b offers some of the benefits of each wheelsize, which is effectively what you are suggesting a "mixed wheel" bike would offer. I'd say with mixed wheels you'd get the disadvantages of both and you may as well go full 29" or as the market goes 650b over 26", go for a 650b bike. All mixed wheels would do is add even more confusion to an already confusing market where 650b is marketing as 27.5" when it isn't, adding 67ers or 79ers isn't going to help that and far as I can see it adds little, if any benefit to the ride of a bike and as someone else pointed out, just adds inconvenience when you have to carry 2 tubes with you. It's been tried before and it didn't catch on, otherwise we'd still be riding these -

EdW

What I'm suggesting is that most of the advantages a 29er has over 26 come from it's larger front wheel. And most of the advantages 26 has over a 29er come from it's smaller rear wheel.
So, logically a best of both worlds 'do it all' platform would be something like a 69er. But for some reason the bike industry has overlooked this & given us the flawed compromise that is 650b.
Given that the front & rear wheel have different responsibilties it seems stupid to say that they MUST be the same.

cooldad

They don't have to be the same, it's just a PITA to have different sizes.

The Rookie

cooldad wrote:

it's just a PITA to have different sizes.

This, as the weather worsens in autumn (gets better in spring - well sometime) I tend to put my next 'grippier' tyre on the front from what I have fitted and the old front on the rear and so on.

Hob Nob

EdW wrote:

The Enduro 29 is compromised in comparison to a 26" Enduro in that it's chainstays are longer, 10mm less travel, the pivots/linkages positioning may not be in the optimal position, the wheel itself will be either heavier, flexier or more expensive.
I am suggesting that a mixed wheel size Enduro would be better than both the 26 & 29 versions.

Why is it a compromise? There is enough clearance on the frame to run another 10-15mm travel if they wanted to, maybe they felt the balance was right at 155mm of travel. As for suggesting the linkage/pivots 'may' be in the wrong place is pure speculation at best.

The wheel itself will be heavier, but the reality is, the difference is negligible, as is flex. Cost? Why would that be any different?

Seeing as the 26" Enduro will comfortably take a 650b wheel, why not chuck a 29" 160mm Pike on the front & see how it works.

lawman

The problem that leads to though is a handling imbalance. You get the front wheel monster trucking over things and a smaller back which can't keep up. So while yes in terms of rollover it makes sense, but what about the other compromises? You don't get the added rear wheel traction of a 29er with a 69er, so in that sense it's no better than a regular 26" bike. Modern bike design has led to the point 29er's are at now, that the geometry of the bikes is more important than wheelsize.

EdW

You say that geometry is more important than wheel size.
This is exactly my point. By adding a constraint that both wheels must be the same size, you are introducing an obstacle to achieving that ideal geometry.
For example, it could be that the ideal geometry for the ultimate AM bike (whatever that is) can be best achieved by having 29" front wheel with 130mm fork, & a 650b rear wheel with 150mm rear travel. I'm not saying that is the case, but we will never know just because some people don't want to carry an extra inner tube. We should at least explore all possibilities.

Kowalski675

EdW wrote:

& given us the flawed compromise that is 650b.

Surely all compromisesa are flawed. That's the nature of a compromise...

DodgeT

EdW wrote:

some people don't want to carry an extra inner tube

Just carry 26" tubes, they'll fit 650b and 29er easily.

supersonic

There is no such thing as an ideal geometry, it is personal preference.

Northwind

lawman wrote:

The problem that leads to though is a handling imbalance. You get the front wheel monster trucking over things and a smaller back which can't keep up.

You mean a bit like a hardtail, but with about 1/10000000th as much of a difference?

I can see some easily led people going for it with 650/26- not easy to swap rear wheels in a frame, and some glaring issues with it (raising BB heights mainly) but forks are easy. But the truth is the difference between 26 and 650b is still too small to be worth bothering with so half the difference is going to be even more of a waste of effort.