Bike Gremlin

I have Claris 2400 road bike STI levers.

I love drop bars, but also love going off road and ride on lots of bad roads. Had a side wall of my 4-seasons 28mm tyre cut just recently, while city commuting!

Anyway, a friend wants to swap frames - he needs a road bike frame, I need a "treking" frame, with room for 27 mm tyres AND mudguards. His frame and wheels have disc brakes.

I'd like to use the disk brakes with my current STI-s and drop bar. So, the question is:

Will Avid BB5, or Shimano M375 mechanic brake callipers work with Super SLR STI-s?

I understand the problem with non Super SLR STI-s is too short cable pull. That means a lot more brake power, but too short a travel - pads would need to be set up too near the disc in order to start braking before the lever bottoms out.

Super SLR has a bit more cable travel, more similar to a standard linear pull lever (i.e. MTB V-brake lever), which should work. Am I correct? Has anyone tried this setup?

Tim_Iowa

The difference in cable pull between road and MTB is much greater than the slight changes from SLR to Super-SLR. It probably won't work.

Possible solutions:
* Use V-brake compatible brake levers. No STIs have this compatibility, but Gevenall Retroshifts do.
* Use road-pull compatible disc brakes with any STIs. Avid BB7R is one example.
* Upgrade to Shimano ST-RS685 STIs, which include hydraulic brake calipers
* Use "Travel Agent" devices to translate the cable pull from road to MTB.

Bike Gremlin

Thank you for your reply. I have just measured the amount of cable pull on the road bike and on the MTB (idiot didn't think of that before asking! ).

MTV V-brake pulls 28 mm of cable, while road bike Super SLR pulls 15 mm. That answers my question.

Tim_Iowa

There you go. It's good to know how different they really are.

Measure measure measure!

It's like the folks who say "what tire can I fit on this frame?" when a quick measurement of the bike in front of them would answer their question.


I have a Foundry Auger (carbon cyclocross bike) that uses BB7R discs with SRAM road brifters. The BB7R's are OK, but not fantastic. I've purchased some Tektro Hy/Rd brakes to upgrade, but haven't got around to fitting them yet.

fietsbob

There is a Inline 'travel agent' but you're better off using a road short pull disc caliper ..

Both Avid BB5&7 come in road and MTB versions.

TRP 'Spyre' has people liking Them , double acting cable brakes, 'Spyke' is the MTB version.



not unusual, Few people Measure things for themselves Here , and supply that data .

Bike Gremlin

I live in a small market, so the only option for road disc callipers is to import them. Which means high customs and post costs.

Not sure, still considering options.

Tim_Iowa

I've had good luck--and great prices--ordering from Bike-discount.de in Germany. I don't have to pay any customs, just a 23-Euro shipping fee to the US. Perhaps they'd still be reasonable for you in Slovenia?

Bike Gremlin

Customs here are crazy. It's Serbia, outside of European Union - so much worse. Avid BB5R cost around 60 euros pair, but would cost me around 100 euros to my address.

A friend has tried regular MTB BB5 with non super SLR road brifters and it worked great, but was a bit squishy feeling on levers (too much leverage). Super SLR has a bit longer cable pull, so it might work. He ordered BB5R which were a bit weaker, but felt better at the levers - because of accurate cable pull ratio.

So now I'm considering testing regular MTB callipers before buying. If it doesn't work well, I'll pass.

ultraman6970

You need something like the avid bb7 road sl (i think)... those work with road brake levers. The other option is to find travel agents that change the travel of the cable, no clue if somebody is still manufacturing those things.

Wilfred Laurier

Travel agents are still around, I think. They work great, but are a bit ugly. Problem Solvers Travel Agent Silver with Silver Roller