Why is my bike hard work?

[reohn2]

.......Reohn said Chrinas which are getting towards lighter (510g for 700C) but are they available in 26"?

They are indeed only available in 700C, so I stand corrected.

[531colin]

http://www.rigida.com/en/products/mtb/rims-3/snyper....

[meic]

The lightest rim that I can come up with is the Snyper at 500g (560g in 700c)
At 17mm bead width it will easily take 28mm and should go even lower.

Looks like Colin agrees.

[mill4six]

I'm gonna try the new wheel route, if it can be done fairly cheaply... Can anyone recommend some light-ish, narrow-ish 26" wheels please?

The wheels that transformed my MTB were Mavic rims on Deore hubs from Merlin Cycles. They are not superlight, they are XC wheels but lighter than the horrible cheapies they replaced. I got them one Christmas with some other bits, built up the bike and went for a test ride in torrential rain. The bike really seemed to fly and I love it still. I have since used it with 25mm Specialized all condition pro tyres (road) in a triathlon with the bars as low as they go and the stem upside down, a real bum up head down position and it's only a couple of minutes slower over a 25km sprint than my new road bike. Not bad for a nasty, heavy old MTB with skinny tyres, if the ride is harsh I still managed LEJOG on it (albeit with some pain!). Having said that, now that I have a new road bike the MTB might get it's knobblies back. Good luck, I've read all the above and I still think it's down to the quality (or lack thereof) of your hubs although no doubt the other stuff contributes. I'm enjoying the fat/thin tyre debate, personally I choose thin to go fast and fat to go long, I won't do LEJOG distance on 25mm again.

[meic]

Another tyre which is a "proper" fast tyre in 26" size.

http://www.spacycles.co.uk/products.php ... 0s142p1718

[Mick F]

I won't do LEJOG distance on 25mm again.

I rode my JOGLE on tyres I can't remember, but they were probably 23mm, and I did my Double E2E(1800miles) on 20mm. Also my Grand Tour of 1400miles on 20mm too.

I won't do E2E again, but if I did, they would be 23mm max.

[CREPELLO]

This chap seems to know what he's doing. I thing I'd go with what he's building.

[PH]

You could try and borrow a pair of better wheels before you buy. Unless there's something seriously wrong with yours I'd be surprised if they made that much difference.

[531colin]

I won't do LEJOG distance on 25mm again.

I rode my JOGLE on tyres I can't remember, but they were probably 23mm, and I did my Double E2E(1800miles) on 20mm. Also my Grand Tour of 1400miles on 20mm too.

I won't do E2E again, but if I did, they would be 23mm max.

Yeah, but Mick, you are riding a 531c lightweight. your frame/forks are much more compliant than the OP's ATB frame.

[531colin]

You could try and borrow a pair of better wheels before you buy. Unless there's something seriously wrong with yours I'd be surprised if they made that much difference.

Wheels AND TYRES would be a much better "borrow"......Unfortunately I dont have anything suitable, my stuff in 26" is all chunky off-road stuff.

[531colin]

This chap seems to know what he's doing. I thing I'd go with what he's building.

What? A beardie man with sandals?

[Mick F]

..... your frame/forks are much more compliant than the OP's ATB frame.

Is this true?
I'm sure I've read on these pages that it's a myth that frames are "compliant" and that the only thing that gives suspension are the tyres.

Personally, I reckon that forks flex too, but not the frame. Frames are rigid vertically.

[CREPELLO]

This chap seems to know what he's doing. I thing I'd go with what he's building.

What? A beardie man with sandals?

But he sure looks like he knows how to play that harp!

[531colin]

..... your frame/forks are much more compliant than the OP's ATB frame.

Is this true?
I'm sure I've read on these pages that it's a myth that frames are "compliant" and that the only thing that gives suspension are the tyres.

Personally, I reckon that forks flex too, but not the frame. Frames are rigid vertically.

I'm sure its a question of degree.
If you run 2" tyres at 50psi, the "give" in the frame/forks is so slight its not worth considering.
I think the OP is running 90 to 100psi in inch and a quarter tyres, which must feel like solid tyres. Then I think the spring in a 531c fork would be very welcome. I dont think a triangulated structure like a bike frame would flex very much in a vertical plane, but there is some lateral flex in the BB area...hold the bars in one hand, the saddle in the other hand, and push the BB with your foot...its quite springy. That flex is the enemy of efficiency, but probably contributes to "comfort".
Certainly, lightweight frames have a different ride "feel" to heavy ones, crashing through the potholes.
I think the OP has the worst possible combination in all of this.
He has an MTB frame. OK, its butted cromo, but these things are over-engineered so that teenage boys dont bend them too often to be a problem for the manufacturers warranty department. I bet the "thin" middle bits of his frame tubes are thicker than the "thick" ends of Mick's 531c. Then he puts 90-100psi in the tyres. I'm sure that combination would make my fillings rattle, and I think this bike is hard work due to "bump losses" - you have to put in all the energy thats wasted in bouncing the bike/rider around.
I think I already said before on this thread, a bike needs to be stiff enough for efficiency, and compliant enough for comfort, and thats a fine line to tread.

[531colin]

Sorry, chaps, I've doubled up on this, trying to edit it......now Ican't delete this...

..... your frame/forks are much more compliant than the OP's ATB frame.

Is this true?
I'm sure I've read on these pages that it's a myth that frames are "compliant" and that the only thing that gives suspension are the tyres.

Personally, I reckon that forks flex too, but not the frame. Frames are rigid vertically.

I'm sure its a question of degree.
If you run 2" tyres at 50psi, the "give" in the frame/forks is so slight its not worth considering.
I think the OP is running 90 to 100psi in inch and a quarter tyres, which must feel like solid tyres. Then I think the spring in a 531c fork would be very welcome. I dont think a triangulated structure like a bike frame would flex very much in a vertical plane, but there is some lateral flex in the BB area...hold the bars in one hand, the saddle in the other hand, and push the BB with your foot...its quite springy. That flex is the enemy of efficiency, but probably contributes to "comfort".
Certainly, lightweight frames have a different ride "feel" to heavy ones, crashing through the potholes.
I think the OP has the worst possible combination in all of this.
He has an MTB frame. OK, its butted cromo, but these things are over-engineered so that teenage boys dont bend them too often to be a problem for the manufacturers warranty department. I bet the "thin" middle bits of his frame tubes are thicker than the "thick" ends of Mick's 531c. Then he puts 90-100psi in the tyres. I'm sure that combination would make my fillings rattle, and I reckon this bike is hard work due to "bump losses" - you have to put in all the energy thats wasted by bouncing the bike/rider around.
I think I already said before on this thread, a bike needs to be stiff enough for efficiency, and compliant enough for comfort, and thats a fine line to tread.