Poor brakes

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Ergle

Über Member
The brakes on my bike are not good at all. It's a Thorn Sherpa bike with drop handlebars, Tiagra STI levers and 26" wheels. I also have interrupter levers on the tops because I like to ride on the tops sometimes. I never brake on the hoods - it's too awkward.

I did have Avid Short6 cantis front and rear, but couldn't get the brakes to be nearly as good as my Specialized MTB, which has V brakes. The MTB brakes are great - with just two fingers on the levers the bike stops on a sixpence.

I tried swopping the V brakes onto the Sherpa - no good (yes I know you're not supposed to but I had a free afternoon). I adjusted the Avids so that the straddle wire was as flat as it could go - still no good.

I then tried a pair of sticky out type cantis on the front - I bought a set of Tektro CR720's - these got great reviews from Chris Juden, CTC's technical officer. Still no good.

The brakes are seriously underpowered against the MTB. I've calculated the mechanical advantage by measuring finger travel against brake shoe travel. The bar top is comparable with the MTB at about 4mm finger travel for 1 of shoe travel. With the hoods, it is 6:1 which is half as much again as the MTB so should be better. I've cleaned the rims with Scotchbrite - even tried the MTB front wheel on the Sherpa- makes no difference.

I haven't tried the MTB levers on the Sherpa - this would involve changing to flat bars, which I don't want to do. I haven't tried different pads such as Kool Stops - I will try this eventually, but think the problem is more than can be solved with a change of pads. The CR720's came with new pads of course.

I've put some pictures of the setup below - I'd welcome some ideas as to how to solve this - I've run out of them.
 

gaz

Cycle Camera TV
Location
South Croydon
Your pad looks warn down in the second image, how deep are the groves in it?
 

buddha

Veteran
What is braking like from the drops?

I recently switched from V's (with flat bars) to canti's (with drops) on the same bike. From the hoods braking is okay, but could be better. From the drops it's similar to the V's - though not as good. Though over the past few months I've been finding it easier to brake from the hoods - getting used to the new setup.

I take it you've gone through the changing the angle of the bars, moving the position of the levers routine.
 

jimboalee

New Member
Location
Solihull
gaz said:
Your pad looks warn down in the second image, how deep are the groves in it?

Yup, worn out.

The blocks are probably full of small grains of road grit and are wearing the rims at an abnormal fast rate. I wouldn't be suprised if the block friction surface is glazed.

When blocks start to get inefficient, take a rough file or surform to them to cut the grit out. If there's not enough meat left, replace the blocks.
 

gwhite

Über Member
I would guess that the problem may be that you're using the Tektro blocks that came with the brakes. These are bad as with most Tektro blocks, and if you exchange these for Koolstop Salmon ones I'm sure you'll see a huge improvement.
 

gouldina

New Member
Location
London
redjedi said:
+1 to new blocks needed, before you try other solutions.

Kool Stop Salmons are my favourite.

+2. I've got Short 4s and replacing the blocks with Kool Stop salmons has made my previously rubbish brakes as good as the Vs on my old hybrid - i.e. very good.
 
OP
OP
Ergle

Ergle

Über Member
gwhite said:
I would guess that the problem may be that you're using the Tektro blocks that came with the brakes. These are bad as with most Tektro blocks, and if you exchange these for Koolstop Salmon ones I'm sure you'll see a huge improvement.

Thanks to all for replies. I took your advice and ordered a set of Koolstop Salmons. They arrived today and are now on the front brakes. Great improvement - I'll do the back ones tomorrow. I guess I could have saved the £19 the CR720's cost me and bought the KS's in the first place and fitted them to the Shorty 6's - but at least I now have something new and shiny on the bike.
 

gouldina

New Member
Location
London
Ergle said:
Thanks to all for replies. I took your advice and ordered a set of Koolstop Salmons. They arrived today and are now on the front brakes. Great improvement - I'll do the back ones tomorrow. I guess I could have saved the £19 the CR720's cost me and bought the KS's in the first place and fitted them to the Shorty 6's - but at least I now have something new and shiny on the bike.

Yay! I did the same as you and just did the front ones first resulting in a significant improvement. Replacing the back ones too though took it to a level of braking I'm completely comfortable with. Prior to that, I couldn't ever lock the back wheel - not that I want to particularly but lacking the brake power to do so is a bit worrying.
 
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