V brake comparison, avid sd7 Vs SL?

[ishaw]

I've got too many v brakes and need to come up with a way to part with some. Simplest way seems to be which are better. I've done some online research and am still none the wiser, though a bit more familiar, so thought I'd ask on here for opinions on performance and durability.

I have SD7s in grey with the SD 7 logo, and some lighter colour SLs with the single digit text rather than SD.

Which are newer? I know the SLs have titanium hardwear, so presumably slightly lighter than the 7s, but are the arms pretty much the same or is there weight saving there too? Most things I've read suggest they are pretty similar. I have an ends with of Avid Tis and would like to find another ends worth, are these essentially SLs rebranded?

I might as well ask how they compare to the red Shimano DX brakes, and also the last Shimano XT v brakes (780?) as I have these too, plus m95x and m970 v brakes as I've a few pairs.

Cheers

Ian

 

[CassidyAce]

Everything else being equal (cables, levers, pads, set up, etc.), I doubt if there will be much discernible difference in braking performance between any of those callipers. Even if you install a cheaper set of Tektro or Clarks V brakes, there would still be little or no discernible difference I expect. The reason is that the mechanical advantage of the callipers depends on their length, which is pretty much the same for all of them. The other key measurement is the distance between the pivot and brake pad, and that's determined by the position of the brake boss relative to the wheel's rim, not by the callipers. If the callipers flexed under braking force, that would affect performance, but I'm not aware of any V brakes having a reputation for flexing (whereas seat stays flexing is a well known issue).

The design of the levers is likely to make more difference than the callipers. If you Google 'mechanical advantage of bike brakes', you will find more detailed explanations. @hamster tends to be very good on this sort of topic too. Note, though, that you can have too much mechanical advantage; it's getting the balance right that's important. Given that, I would perhaps test the return springs to see if there's any significant difference.

As far as durability is concerned, I couldn't really say. My impression is that due care and servicing make more difference than the brand or model.

 

[tintin40]

Are you using different brake blocks?

 

[dandy1]

Agreed... For me it's how you set them up and which brake pad you use. Koolstop pads for me and I've never had an issue with squealing or braking. I do think the parallel push design (lx, xt, xtr) tend to work a bit better though?

 

[ishaw]

Thanks so far. Let's pretend for the moment that I'm not asking about set up or blocks, but just the brakes themselves and how they compare/which are better, lighter, stronger, more durable etc.

 

[hamster]

IIRC the arms are pretty much identical, the Ti bits are a couple of mounting bolts and that's all.
I don;t think parallel push works in any different way - what matters is the force on the brake block and parallel push isn't going to change that. The biggest factor is decent cable outers and noodle.

 

[slackboy]

Thanks. By decent do you mean properly cut and formed, or is some outer cable just better quality? Any recommendations for good quality stuff?

 

[hamster]

Proper preparation is definitely a big plus - I always tip-off the ends of the outer on a bench grinder to get it totally flat.

Cheap outers don't have the spiral nicely snug and it then compresses under load, giving weak braking as it uses up precious lever travel. V's being long travel-low force aren't as susceptible as cantis. Something like K-Ble SRAM, Shimano or Black Snake are all decent. If you buy outer off the reel from your LBS it needn't cost a fortune. However I tend to buy the kits as the extra ferrules and sealed outers are often worth it in my view.

 

[ishaw]

Cheers for the input. I've read that the newer versions had lighter arms, but not sure which are newer, logos between the sls and SD7s are different. I'll weigh them at some point.

Annoyingly the sl levers aren't as nicely finished as the arms, the Sd7 levers look cooler imho, similar ish to the ultimate levers in look (fortunate to own s full set of these beauties).

If there's little difference in the brakes themselves aside from the ti bolts on the sls, seems logical to keep them and let a set of the SD7s go.

Is there much difference between the avid SD7/SLs and the red dx brakes?

I do like the xtr Vs but fancy a change on a build as I've usually gone full xtr and am very familiar with them and they are very very good as long as they are not rattly.