Another rear brake problem.

[Flyingblind]

Having sorted my frame thread issue the brake arms fit fine with free movement and no play. So this afternoon I cleaned and greased the bearings, put on a new cassette and tried the rear wheel in the frame only to find the brake pads do not reach the rim. They need to move out another 20mm but the slot is not long enough. The wheel is the correct size, 26 in.
Can you get brake arms with the slot further out or would a different brake type other than V brakes have been fitted?

 

[Cycleops]

I assume we are talking V brakes on bosses and you have a mountain bike. The only thing I can think of is you have road V brakes which may have a different reach due to the 700c wheels.

 

[Flyingblind]

It's a Saracen X-ray Pro MTB frame. The position of the brake boss seems to about 20mm closer to the wheel spindle compared to my other bikes but otherwise looks identical. Looking at the bike specs that can still be found online it should be a standard 26 wheel.

 

[Spiderweb]

Pic please

 

[Flyingblind]

Ok. Will try and put a pic on tomorrow afternoon as going to work now and sleeping in the morning.

 

[Flyingblind]

Ok, as you can see, the brake pads do not reach the rim because the brake boss is 230mm from the wheel spindle rather than 250mm which is the norm. Either the bike has been made for a smaller wheel despite the specification stating 26 in and that size being a good fit for the frame or a different brake arm than standard needs to be fitted. It's a little dispiriting as I only needed to fit cables, chain and tire and job done.

 

[Cycleops]

Oh dear, looks like the frame makers have made a mistake, difficult to imagine it was made for smaller wheels, but you never know. Don't despair, all is not lost! Do I spy some fittings for disc brakes? If you've never used them before they give far superior stopping power and the cheaper cable operated versions are just sharp. You'll need new hubs lacing on of course. I've just got a Specialzed with discs and I'd never go back to rim brakes if given the choice.
Are the front forks the same?

 

[si_c]

I'm thinking that maybe it was made for cantilevers not v-brakes.

 

[Cycleops]

I always thought cantis had the shared the same mounting dimensions as Vs?

 

[Flyingblind]

It is a little weird, isn't it? The frame must have been used as it is somehow. Maybe, as cycleops has suggested, it had discs fitted. The forks I put on can only accept V brakes but converting the rear to disc is one possible option although that is moving away from my original gaol of quick, easy and cheap. The other two options that are possible is a) I have tracked down some Taiwanese universal brake arms on ebay that allow you to fit 700c wheels in a 26 frame for a little under £30 which is a bit pricey but easy to do or b) extend the brake blocks out with a little plate with a couple of holes drilled. One to bolt to the slot and the other to take the block. Yes, I thought the difference between Vs and cantis was the method of operation, one being a side pull with a noodle and the other being a center pull on a linking cable.
Thanks for your input. Even if a solution is not readily available I find sharing a problem helps me think a bit better and goodness knows I need all the knowledge I can get.

 

[Spiderweb]

I always thought cantis had the shared the same mounting dimensions as Vs?

They do.

 

[Flyingblind]

Oh dear. It was quick and easy to make some brackets out of some angle aluminium I had lying around and it worked really well with the pads on the rim perfectly. I then fitted a tyre and low and behold the arm ends are too short and the cable will drag on the tread when fitted. I should have seen that one coming. The arms are a standard length, 105 mm or maybe 107 mm. The longest easily obtainable arms are 115 mm which would clear by maybe 10 mm which is barely enough, 20 mm would be better. Or go for those Taiwanese arms which are 125 mm long but £30 aside I wouldn't get them till the back end of August.

I really didn't want the faff and expense of converting to a disc but will have another look at that. There is also a hole to mount caliper brakes which are another option but I believe you need slightly different brake levers, is that right?

 

[Cycleops]

'There is also a hole to mount caliper brakes which are another option but I believe you need slightly different brake levers, is that right?'
Don't think so.

 

[Andy_R]

'There is also a hole to mount caliper brakes which are another option but I believe you need slightly different brake levers, is that right?'
Don't think so.

Unfortunately you do....they have a different mechanical advantage to V brakes, so the lever needs to be matched to them unless you use a travel adapter.

 

[Flyingblind]

Just had a look at travel adjusters and the impression I'm getting is that they are more for being able to keep your levers if moving to V type brakes but then my impressions have been known to be completely wrong. Think I might just beg borrow or steal or get some calipers of eBay and stuck it and see and take it from there. I could do with getting something sorted sooner rather than later now the school/uni holidays have kicked in.