Found the perfect bike for people who love Thailand

[moonoi]

You forgot:

Torque: massive torque, specially on the front wheel that stress the rim and spokes. That doesn't exist on the old style brakes. No Radial spokes possible. Need 2 or 3 cross

Yes, torsional stress is an issue, but only with cheap/lightweight wheels. In 2013, I broke 10-12 spokes of my Roval wheels running down Doi Pui on fast tracks. I finally had enough and rebuilt both wheels.

A rim brake can be made suprisingly strong, equalling or exceeding the breaking power of a disk break. For example, trials bikes often use huge rim breaks on roughened rims. The main disadvantage of rim brakes is that they do not perform well/consistent in mud and water. Also, rim overheating and tyre damage are still problems, although it's not very common.

Of course, disk brakes can overheat as well. Yesterday, Kelly McGarry had a big crash in China. Front break overheated and gave out... going down a 50% gradient.

Cheers, CM-Expat

I'd say that rim brakes would have probably suffered the same fate, even Kelly said his 97kg weight coupled with 1000ft of 50 degree stairs at race pace, were probably the reasons his brakes overheated and essentially became a runaway train, lucky he escaped with just cuts and bruises requiring a few stitches, it looked a lot more serious for him that it eventually turned out. Nothing left of his wheels though!

[Rhys]

Nice try but no... ATBs...more practical and affordable..

[bobfish]

Looks like that back brake is still okay!

[T_Dog]

You forgot:

Torque: massive torque, specially on the front wheel that stress the rim and spokes. That doesn't exist on the old style brakes. No Radial spokes possible. Need 2 or 3 cross

Yes, torsional stress is an issue, but only with cheap/lightweight wheels. In 2013, I broke 10-12 spokes of my Roval wheels running down Doi Pui on fast tracks. I finally had enough and rebuilt both wheels.

A rim brake can be made suprisingly strong, equalling or exceeding the breaking power of a disk break. For example, trials bikes often use huge rim breaks on roughened rims. The main disadvantage of rim brakes is that they do not perform well/consistent in mud and water. Also, rim overheating and tyre damage are still problems, although it's not very common.

Of course, disk brakes can overheat as well. Yesterday, Kelly McGarry had a big crash in China. Front break overheated and gave out... going down a 50% gradient.

Cheers, CM-Expat

I'd say that rim brakes would have probably suffered the same fate, even Kelly said his 97kg weight coupled with 1000ft of 50 degree stairs at race pace, were probably the reasons his brakes overheated and essentially became a runaway train, lucky he escaped with just cuts and bruises requiring a few stitches, it looked a lot more serious for him that it eventually turned out. Nothing left of his wheels though!

ImageUploadedByTapatalk1432535171.398576.jpg

Not the first bike he has destroyed. He should have switched to a better rim sponser after his first failures. (Okay, this is a bit extreme for any rim!)

http://www.bikemag.com/videos/video-kelly-mcgarrys-rampage-crash/

Edited May 25, 2015 by T_Dog

[bobfish]

This thread drift on disc vs rim brakes is enlightening!

After a bit of google research it appears Trials bikers do prefer a [usually hydro] rim brake on the back. That's for no modulation - on or off - less spoke distortion and frame distortion/ breakage[ less leverage on the chain/seat stays]. Any trialists know better?

I think rim brakes will have a place for specialised events; eg on TT bikes for flat races etc.

Interestingly, it seems that with rim brakes riders only achieve around 70% of maximum braking effect do to the lack of modulation approaching maximum braking coefficient. Even less so in the wet. Disc brake users achieve much higher; around 90%. Of course, there is always the highly skilled rider who can do better - anyone hereabouts??

[h90]

You forgot:

Torque: massive torque, specially on the front wheel that stress the rim and spokes. That doesn't exist on the old style brakes. No Radial spokes possible. Need 2 or 3 cross

Yes, torsional stress is an issue, but only with cheap/lightweight wheels. In 2013, I broke 10-12 spokes of my Roval wheels running down Doi Pui on fast tracks. I finally had enough and rebuilt both wheels.

A rim brake can be made suprisingly strong, equalling or exceeding the breaking power of a disk break. For example, trials bikes often use huge rim breaks on roughened rims. The main disadvantage of rim brakes is that they do not perform well/consistent in mud and water. Also, rim overheating and tyre damage are still problems, although it's not very common.

Of course, disk brakes can overheat as well. Yesterday, Kelly McGarry had a big crash in China. Front break overheated and gave out... going down a 50% gradient.

Cheers, CM-Expat

I'd say that rim brakes would have probably suffered the same fate, even Kelly said his 97kg weight coupled with 1000ft of 50 degree stairs at race pace, were probably the reasons his brakes overheated and essentially became a runaway train, lucky he escaped with just cuts and bruises requiring a few stitches, it looked a lot more serious for him that it eventually turned out. Nothing left of his wheels though!

ImageUploadedByTapatalk1432535171.398576.jpg

Is this a carbon rim?

Carbon brakes instead of deformation, I always doubt if it is suitable at all. I once hit a large stone with high speed on the road bike. The Aluminum Rim was of course broken, deformed, but it hold enough that I could even go home with brake fully opened. Carbon breaks.

For such extreme things, very heavy rider and and stairs, why they don't install a disc break AND a rim brake?

[moonoi]

You forgot:

Torque: massive torque, specially on the front wheel that stress the rim and spokes. That doesn't exist on the old style brakes. No Radial spokes possible. Need 2 or 3 cross

Yes, torsional stress is an issue, but only with cheap/lightweight wheels. In 2013, I broke 10-12 spokes of my Roval wheels running down Doi Pui on fast tracks. I finally had enough and rebuilt both wheels.

A rim brake can be made suprisingly strong, equalling or exceeding the breaking power of a disk break. For example, trials bikes often use huge rim breaks on roughened rims. The main disadvantage of rim brakes is that they do not perform well/consistent in mud and water. Also, rim overheating and tyre damage are still problems, although it's not very common.

Of course, disk brakes can overheat as well. Yesterday, Kelly McGarry had a big crash in China. Front break overheated and gave out... going down a 50% gradient.

Cheers, CM-Expat

I'd say that rim brakes would have probably suffered the same fate, even Kelly said his 97kg weight coupled with 1000ft of 50 degree stairs at race pace, were probably the reasons his brakes overheated and essentially became a runaway train, lucky he escaped with just cuts and bruises requiring a few stitches, it looked a lot more serious for him that it eventually turned out. Nothing left of his wheels though!

ImageUploadedByTapatalk1432535171.398576.jpg

Is this a carbon rim?

Carbon brakes instead of deformation, I always doubt if it is suitable at all. I once hit a large stone with high speed on the road bike. The Aluminum Rim was of course broken, deformed, but it hold enough that I could even go home with brake fully opened. Carbon breaks.

For such extreme things, very heavy rider and and stairs, why they don't install a disc break AND a rim brake?

No, as you can see from the picture, it is an aluminum rim, although for this impact the result would have been the same.

Or why not 2 disc brakes at the front, with 6 pot calipers, like a high performance motorcycle?

Ordinarily his setup would be fine, as with all extreme sports, failures can happen when right on the edge. I'd change brake sponsor though if I were him ;-)

[h90]

Yes, torsional stress is an issue, but only with cheap/lightweight wheels. In 2013, I broke 10-12 spokes of my Roval wheels running down Doi Pui on fast tracks. I finally had enough and rebuilt both wheels.

A rim brake can be made suprisingly strong, equalling or exceeding the breaking power of a disk break. For example, trials bikes often use huge rim breaks on roughened rims. The main disadvantage of rim brakes is that they do not perform well/consistent in mud and water. Also, rim overheating and tyre damage are still problems, although it's not very common.

Of course, disk brakes can overheat as well. Yesterday, Kelly McGarry had a big crash in China. Front break overheated and gave out... going down a 50% gradient.

Cheers, CM-Expat

I'd say that rim brakes would have probably suffered the same fate, even Kelly said his 97kg weight coupled with 1000ft of 50 degree stairs at race pace, were probably the reasons his brakes overheated and essentially became a runaway train, lucky he escaped with just cuts and bruises requiring a few stitches, it looked a lot more serious for him that it eventually turned out. Nothing left of his wheels though!

ImageUploadedByTapatalk1432535171.398576.jpg

Is this a carbon rim?

Carbon brakes instead of deformation, I always doubt if it is suitable at all. I once hit a large stone with high speed on the road bike. The Aluminum Rim was of course broken, deformed, but it hold enough that I could even go home with brake fully opened. Carbon breaks.

For such extreme things, very heavy rider and and stairs, why they don't install a disc break AND a rim brake?

No, as you can see from the picture, it is an aluminum rim, although for this impact the result would have been the same.

Or why not 2 disc brakes at the front, with 6 pot calipers, like a high performance motorcycle?

Ordinarily his setup would be fine, as with all extreme sports, failures can happen when right on the edge. I'd change brake sponsor though if I were him ;-)

Yes I thought overly complicate.....2 discs...and that is overly complicate, make the disc a bit larger in diameter and bit thicker. For an extreme test it isn't difficult to make a special version.

[bobfish]

Kelly's a big guy and a hard charger; probably not anything available that could have stood the 'test'. Saint brakes [shimano] and Atomlab's DHR wheels seem to be getting some - not entirely fair - stick from this.

[moonoi]

In fairness, I think nothing would survive that, my comment was a little bit tongue in cheek, seeing as he has a habit of crashing and blowing out his wheels this year ;-)

Edited May 26, 2015 by moonoi

[h90]

In fairness, I think nothing would survive that, my comment was a little bit tongue in cheek, seeing as he has a habit of crashing and blowing out his wheels this year ;-)

Of course you can make a rim and breaks that survive that, just not standard equipment.

Off topic: I had a customer 120 kg heavy who claimed to do 2 meter (high??) jumps with the MTB and always seals in the shock absorber blow.

I made him some from heavy duty HPU...they did the job. But I am surprise that the rest of the bike could stand it.....

[moonoi]

The rider weight limit on most bikes is 125Kg, although specialized it's a mere 108Kg. So depending on what he was riding, he may well have been with the frames limits, just the components that may not have been up to spec.