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Rear brake under bottom bracket; maintenance issue?

paudie2005

Hello,

Has anyone experience of using a road bike with the rear brake fitted below the bottom bracket? Is there much maintenance issues if using the bike in wet / winter conditions compared with brakes fitted in the usual position?

I’m looking at a Rose Xeon which has a direct mount brake in this position, it’s my only reservation regarding the bike

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Mycroft H

They'd be a pain to keep clean I would say. Considering all the muck my BB picks up on the back roads here I would avoid them. They are however meant to be easier to center so that's a plus.

07Lapierre

A brake calliper under the BB may be more aero, but from a home mechanics point of view, I'd say the rear caliper would have to be check regularly and may have to be stripped down, re-lubed and re-assembled on a regular basis.

07Lapierre

Mycroft H wrote: »

They'd be a pain to keep clean I would say. Considering all the muck my BB picks up on the back roads here I would avoid them. They are however meant to be easier to center so that's a plus.

That implies its difficult to centre a regular caliper (which its not)

tomasrojo

I'm only posting this in case anyone else was having trouble visualising this. This seems completely bizarre to me. I guess the world of high-end/high-performance bikes is far distant from me.

Eamonnator

I had similar brakes to these on my first MTB, back in 1992. We called them U brakes. They were fine in the dry, but when things got wet and sloppy, they were a pain in the ass. Because they were so close to the ground, they used clog up with muck and gunge. I'm sure, on a road bike, they wouldn't be as impractical.

tomasrojo

Locking up with mini u-lock might be slightly easier at a crowded rack. Only advantage to me I can think of.

iwillhtfu

OP I can't see it getting a lot more abuse than a standard position. It certainly wouldn't put me off a bike purchase and sure everywhere on a bike gets covered in a layer of dirt when out this time of year.

As for maintenance a quick scrub down after a long ride and away you go. If it were on a cx bike or a mountain bike then I could see the need for concern but not on a road bike.

iwillhtfu

sprite0

I actually have a Rose Xeon myself. I find that the rear brake tends to get less less mucky than the rear brake on my Trek roadbike which is in the "normal" position. If anything it is shielded by the bottom bracket. It definitely has not caused any maintenance issues.

Wishbone Ash

Food for thought!

“On a bike that doesn’t need to do a lot of braking that position under the chainstays is OK. But when there have been investigations into the most performance-orientated position of brakes on a frame, it’s been found that underneath the chainstays is pretty much the worst place for a rear brake.

He adds: “Fitting a rear brake underneath the chainstays has the effect of the wheel trying to rip the rear brake off the mounts. At least if you put the brakes at the top of the seatstays, the wheel is only trying to push the brakes into the seatstays, which is impossible.”

http://www.cyclingweekly.co.uk/news/latest-news/are-direct-mount-brakes-the-future-193731

tomasrojo

He adds: “Fitting a rear brake underneath the chainstays has the effect of the wheel trying to rip the rear brake off the mounts. At least if you put the brakes at the top of the seatstays, the wheel is only trying to push the brakes into the seatstays, which is impossible.”

Does that logic not apply (somewhat anyway) to the front brakes? The front wheel is trying to rip the brake off the mounts? Though I suppose if you lock the front brake, the bike will pivot over the front axle.

Lumen

tomasrojo wrote: »

Does that logic not apply (somewhat anyway) to the front brakes? The front wheel is trying to rip the brake off the mounts? Though I suppose if you lock the front brake, the bike will pivot over the front axle.

In any case, it's not possible to generate large braking forces on the back wheel due to weight transfer unloading the contact patch.

Mycroft H

The forces required to rip a brake off It's mount are going to be far in excess of what is normally going to be generated. I've never heard of it happening.

triggermortis

I have the Rose Xeon and the rear brake is a direct mount type, so is held with two screws, so I doubt it is ever going to move from where it should be even with my excessive weight on it..

pedro_colnago

Scott were at that crack too, I'm a Luddite but I don't see the point in putting a brake there, Ud imagine they would get gunked up with road debris but I don't know. Just bike manufactures trying to be different and clever. I've no doubt some cynical git said the same about clip in pedals, carbon fibre frames and internal cabling too tho.
Rose do make lovely frames tho it must be said.

Quigs Snr

Had that type of brake on a cervelo p4... no power.. worthless.

have a trp brake there on a merida reacto.... looks great. .. works better than the p4 but noticeably MUCH weaker than "normal" brakes. have used it as a winter bike and am now giving up on it. mechanism picks up tons of gunk.. constantly seizes.. even the cable seems to need replacement (inner and outer) all the time. Wrong country we are living in for that sort of brake. Shame because I really like the merida.

Esroh

This is not something new.Its actually retro. It was standard break position on bikes back in the day of rod breaks.

tomasrojo

Esroh wrote: »

This is not something new.Its actually retro. It was standard break position on bikes back in the day of rod breaks.

Yeah, forgot about that!

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