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View Full Version : HELP!!!!! my rear brakes don't line up



svacher
10-17-2009, 07:26 PM
Well i guess the title sums it up.
I'm nearing the end of my HR build and started putting back the components and my rear brakes dont line up any more with the rims.
I have gone back through the instructions and i can't see anything I've missed or done wrong but they are no where near.
616617

I think i have the rear drop outs correct 618?

Do i need to remove the brake fittings and relocate them?


Please help as i will be going way too fast for just one brake.

Steve

PeterT
10-17-2009, 10:08 PM
Have you checked if the brakes are on the wrong side? or upside down?

PeterT

SirJoey
10-17-2009, 10:44 PM
Have you checked if the brakes are on the wrong side? or upside down?Hard to tell, but looks like they are both, maybe... :rolleyes4:
If so, a simple fix.

Is that the wheel that belongs with that rear triangle?



http://img3.imageshack.us/img3/49/signaturehalloween.jpg

Richie Rich
10-18-2009, 01:13 AM
...I have gone back through the instructions and i can't see anything I've missed or done wrong but they are no where near.

http://forum.atomiczombie.com/attachment.php?attachmentid=618&thumb=1&d=1255821737

SteveWhen you added the extra dropouts to your existing dropouts, you relocated the wheel so that it can't line up with the brakes.

You'll have to either move the brake mounts or remove the extra dropouts.

....Richie....
.

svacher
10-18-2009, 05:42 AM
I've tried the brakes up, down, left and right but they won't fit, unfortunately i think Rich is right.
When I've added the new dropouts it's moved the wheel back past the limit of the the brake pad adjustment :-(
I think i will have to move the brake mounts. Does anyone have any ideas on the best way to do this, bearing in mind my limited welding experience and the stresses they will be under.

Ohhh bugger :-(

Thanks in advance.

Steve

John Lewis
10-18-2009, 08:28 AM
Before you hack it about go have a look in your LBS.

There is a BMX brake that fits on those posts and acts sort of like a pair of scissors. Just looking I'd almost bet they would fit. Worth a look.

I've not had much luck getting those posts off in one piece. You may need to get some from another bike so you can cut and grind back the tubing. Then cut and grind those down out of the way. I usually silver solder or braze them on. Better yet if you can find some new posts. I have a source and usually buy a dozen or so at a time.

John Lewis

svacher
10-18-2009, 12:39 PM
Yet again this forum has come good again.

I had a number of donor bikes dead on the floor of the garage so i very carefully chopped off a couple of brake mounts and have now welded them back on in the correct position.

They work fine :-)

Thanks again to all for the feedback and suggestions.

Steve

likebikes
10-19-2009, 12:39 PM
You are hitting the same thing I'm looking at. I'm hoping to get my new dropouts set correctly to avoid the problem but it seems you've handled it well enough.

james folkes
12-30-2009, 11:15 AM
You are hitting the same thing I'm looking at. I'm hoping to get my new dropouts set correctly to avoid the problem but it seems you've handled it well enough.

indeed... looking at the plans for the high roller it did strike me that the location of the rear brake posts was a potential problem, i spent ages poring over the build guide but you are right steve, there is no mention of it. on the documented machine a v-brake calliper appears to have been used with the blocks right down by the posts, seemingly that is just about ok, but i see from the photograph that your new tabs are also a bit longer than those in the guide.

i am encouraged to hear that you managed to bodge on some recycled brake posts, presumably a relatively simple jig could be made from a block of wood with two holes drilled in it, have you -or anyone else - got any information about how you tackled this bit?

oh yeah, first post, so err, hello. not built a bicycle before, normally i build loudspeakers but the attrition of my commute to work on a diamond frame is the mother of invention. seems like lots of fun, i'll keep you posted.

james.

Radical Brad
12-30-2009, 11:43 AM
Maybe I will suggest that the studs are going to need transplanting in the plans since this seems to happen to a few builders. I often just dig in my large bucket of brake parts when the time comes, so I found what I needed without cutting the studs.

If you do have to move them, it is not all that difficult. Just carefully cut along the edge with a hacksaw and then tack weld them in the new position, checking for proper pad alignent before welding them completely.

They will be a bit shorter after cutting, but this is never a problem.

Brad

james folkes
12-30-2009, 04:29 PM
hi brad, thanks for the swift response... it doesn't sound like the most challenging of activities, so i think i will probably reverse engineer my post locations for the most hard-line v brake caliper i can lay my hands on. i don't have a box of bits yet (ask me this time next year) but friends more dedicated to two wheeled transport will come to the rescue i'm sure.

whilst you're here, i have another little question about those rear mounting tabs. in figure 59 where the new tabs are shown with the rear wheel in place, they are not perpendicular to the axle. will they flex into position when the axle nuts are tightened or is it perhaps prudent to try and bend them inwards slightly in advance?

these are very minor details though, the plans are clear and thorough, and an entertaining read to boot. after going through them closely a few times i definitely feel ready to tackle all aspects of the project. i decided to rough this one together as a quick and dirty precursor to building a tourmaster, thinking the frame concept is a bit more tolerant to the novice builder's potential shortcomings. the latter i wish to build from the poshest possible tubing: there's a possibility of a broken dawes galaxy super tourist for starters, although some kinds of reynolds tubing are a bit more fiddly to join, requiring silver soldered brazing and possibly the custom construction of lugs, my limited research has suggested. don't fancy that on my first build!

the short wheelbase highroller will be far better suited to the cut and thrust of the daily commute anyway, so much as i am utterly intoxicated by the design of the tourmaster and see it as the ultimate answer to my ultra-long distance holiday ambitions, the shortie is actually the bike i (for which, read my back, neck and bum) need right now.

forgive my lengthy post. i have the enthusiastic zeal of the recent convert when it comes to the subject of diy recumbent building...

james.

Radical Brad
12-30-2009, 06:03 PM
No problemo... you will be riding in no time, I bet.
The dropouts will be fine once you tighten up the axle nuts, and in that photo, I had them loose, which is why there was that small gap shown.

Cheers.
Brad

james folkes
01-04-2010, 09:25 PM
i've started dismantling and chopping for my high roller, one of the brake posts on the rear fork had a seized bolt, so that rather took the decision about possible re-use out of my hands. the rear-end forks come from a bloated raleigh max mountain bike, whilst they are pointlessly heavy in comparison to conventional forks, the unusualy fat tubing is terminated at the drop-out tabs in such a way as to be flush on the inside. this should make sure there will be plenty of space for the cassette and good clearance for the chain path. i think that fat old tube might even be a bit easier to weld too!

looking in you swb gallery i spied the beautiful creation entitled banana boat (http://www.atomiczombie.com/gallery/gallery/randall-rickert/swb.htm), it appears that they have used the seat stays to mount the rear brake, what is more it looks like those seat stays might still be attached to their original drop-out tabs. if so that would be a rather neat solution to the problem of locating one's brake posts, it might even keep the seat stays out of the chain path, and of course it saves you a weld!

i think i might give this a whirl, i'll let you know if it works out.

james.

likebikes
01-05-2010, 01:37 PM
When I welded my posts in place, I used a piece of particle board about an inch by 5 inched and 1" thick for a jug. It's incredibly straight and I was able to make the posts perfectly perpendicular.

John Lewis
01-07-2010, 09:53 PM
looking in you swb gallery i spied the beautiful creation entitled banana boat (http://www.atomiczombie.com/gallery/gallery/randall-rickert/swb.htm), it appears that they have used the seat stays to mount the rear brake, what is more it looks like those seat stays might still be attached to their original drop-out tabs. if so that would be a rather neat solution to the problem of locating one's brake posts, it might even keep the seat stays out of the chain path, and of course it saves you a weld!

i think i might give this a whirl, i'll let you know if it works out.

james.

I have brazed posts to seat stays on a couple of LWB's. The stays tend to flex a bit and the braking is less effective. Next time I will search out thicker stays or reinforce them.

John Lewis

james folkes
01-25-2010, 05:52 PM
ok, bearing in mind what you have said there john i am going to mount the rear brake posts to the fork sections, these are very substantial in my build and will be pretty stiff i'm sure. it will look cleaner and there should be more chain clearance too.

now i'm kind of assuming that it doesn't matter which side of the forks these are mounted... are cantilever or v-brakes particular about which way up they are mounted? it always strikes me that they should be braced up against the frame, otherwise, as is the case with a conventional front brake mount for example, all the breaking force is running through the caliper mounting bolts. this does seem a bit odd, i guess brakes are just mounted in front of the fork to keep them out of the way?

james.

fultondp
01-25-2010, 08:02 PM
I've been told by the usual band of experts "THEY" say that mounting the wrong way round will loosen them up faster. I've done both ways and never noticed a difference with looseness. The only difference I can muddle in my head is flexing the bolt upward makes the brake pads ride up to the wider part of the rim, and grip harder, so it somewhat limits the bend on the bolt. Mounting so the bolt bends downward doesn't self limit, so I could see how theoretically it could cause a brake failure. But in the real world, I don't see how you could really grip the wheel hard enough to cause this to happen. Maybe on a really skinny roadbike with super light weight components.

Darren

likebikes
01-25-2010, 11:02 PM
I can't comment on whether the brakes are more effective on the bottom of the fork or the top, but I welded mine on the bottom, simply because they were already on that side but needed repositioning. Had I thought about it much, I would have welded them on the top of the forks because they interfered with my chain line on the bottom and caused the need for the additional idler. After all the time and trouble carefully aligning them and the difficulty cutting them off and rewelding the first time, I decided to leave them as is, but I would say, look at your chain line before making the decision.

John Lewis
01-26-2010, 08:57 AM
I don't think it really matters which side you fit them.
What you have to watch for is chain clearance and where the cable is to run. On the ones I have, and perhaps some are different, the cable will come out the left side if the brakes are on top of the stay. If I do it the other way it will exit on the right. This may or may not cause a problem with the chain.

One chap here had the brake bosses on the bottom but he had modified the brakes so the cable exited left. He had also done the clever trick of having a set on top too but at a different location so he coud swap his rear wheel between 20" and 26".

John Lewis

likebikes
01-27-2010, 03:54 PM
I'm not having a cable clearance issue as I am using center-pull V brakes, I'm referring to the chain passing under the rear forks where the brakes are hung. I understand what you're saying though.

likebikes
01-27-2010, 04:34 PM
This is what I ended up with. The chain is on the largest cog on the cassette which is a monsterous overdrive gear, I'm not sure if I'll ever use that gear but I thought I'd better accomodate it.



http://i127.photobucket.com/albums/p142/courtnek100/High%20Roller/chainline.jpg

james folkes
02-02-2010, 04:57 PM
i had a go at welding on my brake posts for the rear wheel today, i thought they came out quite nicely.

http://img38.imageshack.us/img38/3845/img0018dl.jpg (http://img38.imageshack.us/i/img0018dl.jpg/)

i chose to angle them so the pads would be relatively straight in their mounts and so that the braking force would not be loading them off-axis. i actually rather enjoyed doing them, they came out well as i said, i should have known at once to be suspicious...

http://img690.imageshack.us/img690/6783/img0021jo.jpg (http://img690.imageshack.us/i/img0021jo.jpg/)

ah! yes, my optimism was, well, optimistic... seems i haven't taken into account the fact that the fork legs are so much further apart than they used to be. the pads don't get anywhere the wheel of course, not even close. whilst i am fast running out of posts, i have not lost heart yet, i simply plan to mount my last remaining pair on some form of outrigger. i shall chop them out of the seat stays they currently reside in, but shall keep the section of seat stay attached, i think it could be capped at one end and fish-mouthed onto the fork at the other... i shall experiment tomorrow.

james.

james folkes
02-02-2010, 05:54 PM
i think it could be capped at one end and fish-mouthed onto the fork at the other...

ah, but it can't... the spring locating tab would then be 90 degrees out of alignment.

i went to the bits box for a rear triangle, came back with so much more... i found the collection of fixings that secure the rear mech (get in!) and a number of other handy looking bits and pieces i had put in a box destined for the workshop, then subsequently lost.

that's put me back on a good footing somewhat, plus the sheer joy of hack-sawing up old frame has added fuel to the fire. i shall take my little seat stay y-shaped assembly and find some ingenious way of using it as a jig to locate the posts as i fix them. i know this failed with the drop-out tabs, but i am sure there's merit in the scheme somewhere.

james.

likebikes
02-03-2010, 01:42 PM
ah! yes, my optimism was, well, optimistic... seems i haven't taken into account the fact that the fork legs are so much further apart than they used to be. the pads don't get anywhere the wheel of course, not even close. whilst i am fast running out of posts, i have not lost heart yet, i simply plan to mount my last remaining pair on some form of outrigger. i shall chop them out of the seat stays they currently reside in, but shall keep the section of seat stay attached, i think it could be capped at one end and fish-mouthed onto the fork at the other... i shall experiment tomorrow.

james.

I found this same problem, I'm sorry I didn't mention it. That is why I ended up using the center pull V brakes. If you have a set available to you try them before doing any more cutting and welding.

james folkes
02-03-2010, 04:24 PM
I found this same problem, I'm sorry I didn't mention it. That is why I ended up using the center pull V brakes. If you have a set available to you try them before doing any more cutting and welding.

ah, bit late for that... to be fair, i can't see v pull's having been significantly better, that far out were my posts. they are mostly salvageable though, the posts that is, and whilst i spent a while faffing around with the new donor set today, i have been pondering the problem this evening and have come up with a few outrigger solutions to try.

there will be photos...

james.

james folkes
02-04-2010, 06:35 PM
you'll love this...

http://img30.imageshack.us/img30/572/img0469xl.jpg (http://img30.imageshack.us/i/img0469xl.jpg/)

i made a new jig based on the still-attached set of posts, then used it to locate the old posts (now getting very short!). the jig clamps to the rim of the wheel to orientate and set the distance, this left the posts floating in mid air; i made a little bridge of weld to tack them in place, then removed the wheel.

with the jig back in place i then patiently layered up the weld material, waiting for each side to cool a bit before applying more. mr mig was sizzling nicely, it's not a great unit but i seem to have got some settings dialled in that i can work with. i gave each side something like 10-15 good squirts, but i still might re-visit as even now they look like they might do with a teeny bit more support. they are pretty solid though, and as you can see they are now exactly where they want to be.

http://img29.imageshack.us/img29/5851/img0475u.jpg (http://img29.imageshack.us/i/img0475u.jpg/)

http://img4.imageshack.us/img4/1939/img0479ft.jpg (http://img4.imageshack.us/i/img0479ft.jpg/)

provided the big snotty pile of weld is of sufficient rigidity to anchor the anchors, i think we can now close the case file on my high roller's rear brake studs. i am pleased with the results, many thanks for the help and guidance.

james.

John Lewis
02-05-2010, 09:46 AM
james, For future reference. When I had a similar situation on a BentecI first welded a short length of tube to each chain stay and then welded the brake bosses to them. I chose a diameter of tube that set the brake in the right position. It worked well.

John Lewis