XTR vs XT vs Mavic

[MintSauce]

 

Rims are stiff enough' date=' so making them stiffer serves no purpose.

[/quote']

 

 

You make lots of valid points, except this one

 

If they CAN make them stiffer....why not?

 

 

 

Because stiff enough is stiff enough.

 

Let me explain. Modern bicycle wheels are stiff enough for anything we throw at them.

 

1) In torsion (We apply on average about 7NM of torque on a rear wheel), the difference in spoke tension from pedalling is in the region of 5% of static spoke tension. It doesn't deform the wheel. Making the rims stiffer therefore serves no purpose. In braking (with hub brakes), the forces are a bit more, but again, with no ill effect to the wheels.

 

2) In cornering, the wheels are subject to NO lateral force (bicycle and motorcycle cornering exerts only radial forces on a wheel). They are already stiff enough to carry our weight and not deflect with any ill effect, so why make them stiffer. Incidentally, a deep section rim is stiffer than a box section by an order magnitude and we don't notice the difference.

 

3) In honking up a hill we apply a small lateral force to the wheel. However, the deflection is less than the space between rim and brake pad. Making it stiffer will achieve nothing.

 

 

Therefore, stiff enough is stiff enough.

 

To use an absurd analogy. Lets make pillow slips stronger and sew them from Kevlar sheeting or.....lets make shoelaces very strong and make them from braided steel cable.

 

Everyday examples abound - make cutlery stronger by forging them from boron steel. Make your office printer stronger by stamping its cover from a sheet of titanium.

 

What purpose do you foresee for stiffer rims?

 

 

 

 

 

 

This industry of ours loves the mantra of "lighter, stiffer, better." I question that.

 

 

I would think that a company that wants to stay ahead of it's opposition would improve their product in any way possible. It sounded at first like you were saying that there's no need for them to improve the product.

 

If they can make them stiffer in some way, then surely as a result they would be able to shed some weight and still make them "stiff enough"

 

Which I guess is probably what they're doing anyway

 

 

 

 

[GoLefty!!]

they do that anyway, they just need to emphasise certain attributes so that you read their advert.

[rock]

ok lets see' date='

 

OF CRC, Hope PRo II hubs will set you back. R2500 for the set, incl VAT.

The Rims will cost you R1600-00 locally.

Revs are around R16 per spoke x64 = R1024

Labour per wheel = R600

 

 

[/quote']

 

who charges R600 per wheel to build!!

[rock]

btw the new agent sells the above mentioned ZTR/Hope/Revolution wheels for R10995.......

[Johan Bornman]

I would think that a company that wants to stay ahead of it's opposition would improve their product in any way possible. It sounded at first like you were saying that there's no need for them to improve the product.

If they can make them stiffer in some way' date=' then surely as a result they would be able to shed some weight and still make them "stiff enough"

Which I guess is probably what they're doing anyway


[/quote']

 

I think over time we do see improvements. It would be silly to say nothing has changed since 1950 when Tulio was still alive and men were men and...... However, improvements come in in spurts, interspaced with periods of insanity. Arguably the previous generation Shimano wheels with spokes hooked into the rims only served to prove that this was a bad idea.

 

But let me make it clear what I believe. There is NO need to make wheels stiffer. Stiff enough is stiff enough.

 

If, like you say they use less material to do that and, they don't sacrifice something else along the way, like durability, then we have progress.

 

 

[Aicorner]

For interest, does "stiff enough" equal "strong enough" - mtb wheels get  hit from the bottom & sides more than road wheels & I think they are subject to considerable lateral & other forces. 

 

If "stiffer" means "stronger" then there's a big difference.

 

HAving said that, my advice is go XT, its cheaper & easier to repair and strong enough so that the hits which damage it willprobably damage the more expensive wheels as well. 

[Johan Bornman]

For interest' date=' does "stiff enough" equal "strong enough" - mtb wheels get  hit from the bottom & sides more than road wheels & I think they are subject to considerable lateral & other forces. 

 

If "stiffer" means "stronger" then there's a big difference.

 

HAving said that, my advice is go XT, its cheaper & easier to repair and strong enough so that the hits which damage it willprobably damage the more expensive wheels as well. 

[/quote']

 

 

No it does not. Ceramic is very stiff but not strong enough for rims.

 

If a wheel were to be subjected to lateral forces, it would fold saddle-shaped aka taco.  It's a simple as this. If they don't taco, they're not subjected to significant lateral forces.

 

We know this, since anyone who has tried to make a box cart out of bicycle wheels would have discovered how poor they perform laterally when they took the first corner at speed. They'd have the scars to prove it.

 

Let me repeat the definition:

 

Strong: The wheel has enough strength to support the intended load without breaking or failing in any way.

 

Durable: The wheel has the ability to carry its intended load over a long distance over a long period of time.

 

Stiff: The wheel does not deflect enough, during normal operation, to touch the brake pads or other frame parts.

 

Therefore, most wheels we know are strong enough and stiff enough. Durability is the problem.

 

 

[Aicorner]

MTB wheels do taco every now & then.  (Often enough for the trick of standing on them to fix to have been developed)  That's why I think they are subject to lateral forces.  Maybe they don't need to be stiffer, but it would be nice if they could be made stronger.   

[Johan Bornman]

MTB wheels do taco every now & then.  (Often enough for the trick of standing on them to fix to have been developed)  That's why I think they are subject to lateral forces.  Maybe they don't need to be stiffer' date=' but it would be nice if they could be made stronger.   [/quote']

 

Of course they do. However, they are only subject to lateral forces when there is a crash of sorts. Cornering and riding along doesn't subject them to such forces. To make them laterally strong they either have to become smaller, the hubs have to become wider  - or all of the above. Nobody wants to do that.

 

Considering how seldom they taco, they are strong enough. Strength comes with a weight penalty.

[GoLefty!!]

ok lets see' date='

 

OF CRC, Hope PRo II hubs will set you back. R2500 for the set, incl VAT.

The Rims will cost you R1600-00 locally.

Revs are around R16 per spoke x64 = R1024

Labour per wheel = R600

 

 

[/quote']

 

who charges R600 per wheel to build!!

 

 

Sorry thats a typo, it should  be Labour for wheels = R600 (i.e both wheels @R300 ea)

[rad006]

ok lets see' date='

 

OF CRC, Hope PRo II hubs will set you back. R2500 for the set, incl VAT.

The Rims will cost you R1600-00 locally.

Revs are around R16 per spoke x64 = R1024

Labour per wheel = R600

 

 

[/quote']

 

who charges R600 per wheel to build!!

 

 

Sorry thats a typo, it should  be Labour for wheels = R600 (i.e both wheels @R300 ea)

 

 

Cajees charge R100 per wheel

 

HAHAHA ok bring on the comments lol

 

Let me guess I wouldnt let Cajees touch my stuff even if they paid me???

[GoLefty!!]

R100 per wheel....

 

Well maybe they have a sweat shop out back..??!!

It takes at least 60min to get a wheel laced up even for an expereince builder. So at R100-00 per hour labour charge I'd say you get what you pay for 

[rad006]

Hahaha hey its called cheap labour....has a distint link with cheap prices lol

And they prob get paid R10 and hour so they have 5hrs to do the job and the shop makes R50

 

[stratus5]

Beware the 2008 XT 775 Hub. I have had mine for six months and the Freebody hub has failed. The photo's below are not mine, but the failure is identical.

 

Whilst I appreciate that any equipment can fail, what I really dont enjoy is the fact that there are no replacement parts in South Africa. You have been able to buy the hub for nearly a year, but Shimano SA has no 775  freehub body on their stock sheets and the old 760 does not fit.

 

775 supposedly available next month. How about a something I can use in the meanwhile?

 

http://www.pvdwiki.com/images/e/e6/XT775-Cassette-Failure-8.jpg

 

 

http://www.pvdwiki.com/images/2/28/XT775-Cassette-Failure-9.jpg

[rad006]

Eish Now what do I buy????

[GoLefty!!]

Firstly that failure is quite rare and in act I'd say that there was probably a manufacturers fault at the factory.

 

Secondly, Unfortunately Coolheat are not very good at replacement parts. They expect you to buy a new wheel or hub whivh I think is disgusting. I buy my spares on-line from Jenson USA or Chainreaction. It's cheaper and the i'll get it faster with less. fuss. In fact out of principal I no longer purchase Shimano components locally. However tht does not dtract from the fact that Shimano's hubs and new wheels are the dogs danglies. the distributor just needs to get it's act together.