Help Frame and parts compatibility

Bartek

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Jun 28, 2010
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#1
I was under an impression that today's frames and parts made by such companies like Shimano are compatible. Thinking that I went out and bought a set of new brakes without asking any questions or telling the store owner what frame I was buying them for. And to my surprise the new brakes seem too short for my frame. Both arms, on front and rear brakes, do not exactly reach down to the rim's braking surface. The pads touch the tires despite being set at the lowest position possible.

Has anyone had a similar problem?

The frame in question is 2010 Trek 1.2 and the brakes are Shimano 105.
It came with Shimano Sora groupset and the arms on those brakes seem to be much longer.
 

Sibreen

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Jul 23, 2010
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#3
Internet says some older models of trek 1.2 need long reach brake calipers. I know shimano do these in the tiagra range (I have them on a steel bike), and there are various tektro models, but not sure about higher-end shimano.

FWIW, new 105 brakes are supposed to be used with new 105 levers - sth about cable pull ratios. Saying that, I mixed sora with 105 5700 brakes and never had any trouble..
 

microcord

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Aug 28, 2012
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#4
No, I haven't had that particular problem. (But I've had plenty of others.)

Think for a moment of (full) mudguards. Bikes do or don't have clearance for them. If they do, the (rim) brakes have to reach around them; if they don't, then the brakes don't have to. And even with no mudguard clearance there's a difference between 700Cx20 and so-called "29 inch" tires. Etc etc.

Without mudguards and with skinnier tyres, the frame designer wants minimal clearance, not just because this looks kewler but also because shorter brakes give you more leverage. (Consider: Given handles of the same length, the shorter the business end of pliers, the stronger they grip.)

Back when I were a lad [sepia mode on], brakes had short- and medium-reach (or long-reach) variants, unless you were buying something very racy, whereupon it was always short [sepia mode off]. But recently I haven't looked.
 
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Bartek

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#5
Have you adjusted the brake blocks, they slide up and down the arms.
Yes, I have. They are set at the lowest position possible.

Internet says some older models of trek 1.2 need long reach brake calipers. I know shimano do these in the tiagra range (I have them on a steel bike), and there are various tektro models, but not sure about higher-end shimano.
Well, that must be the answer. Thank you.
I guess you can never take anything for granted.

No, I haven't had that particular problem. (But I've had plenty of others.)

Think for a moment of (full) mudguards. Bikes do or don't have clearance for them. If they do, the (rim) brakes have to reach around them; if they don't, then the brakes don't have to. And even with no mudguard clearance there's a difference between 700Cx20 and so-called "29 inch" tires. Etc etc.

Without mudguards and with skinnier tyres, the frame designer wants minimal clearance, not just because this looks kewler but also because shorter brakes give you more leverage. (Consider: Given handles of the same length, the shorter the business end of pliers, the stronger they grip.)

Back when I were a lad [sepia mode on], brakes had short- and medium-reach (or long-reach) variants, unless you were buying something very racy, whereupon it was always short [sepia mode off]. But recently I haven't looked.
Trek 1.2 is not really a typical race frame. It's actually a strange design. It could be used as a racing bike, but also as touring machine as it is possible to attach both front and rear racks. And yet there is almost no clearance for mudguards.

Now, I wonder if today's brakes also have different length variants. Perhaps that was over looked when I was buying mine. Thank you.
 

Bartek

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#7
Here, somebody in your situation (a few millimetres one way or the other) is recommended these Shimano brakes (if I understand correctly).

But before paying more money for these or anything else, I suggest digesting the relevant parts of this.
Thanks. That is it. It'a bit disappointing though that before making a purchase we must do a research first. I thought companies eliminated his problem long ago.

Well, thank you all for very helpful replies.
 

microcord

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#8
It'a bit disappointing though that before making a purchase we must do a research first. I thought companies eliminated his problem long ago.
Look, if that were so then there'd be no Surly Pugsley, for example. "We can't make a bike with tyres like that -- Shimano's one-size-fits-all rim brakes wouldn't fit." (Forget disc brakes: they require different this and different that.) And the Pugsley's just an obvious extreme. Your non-extreme bike probably isn't very close to mine and it's likely that we're both glad they're different.

If you think the matter of brake reach is a pain, consider seat post diameters. No, wait, don't consider them; you'd probably doze off.

Shimano isn't to blame. And I suppose that if you have an air of confidence about you when you buy something in a store, the bike store person wouldn't want to question you. (Some customers might get all huffy: "What does this man take me for -- a fool?")

Maybe you can return the brakes. Good luck!
 

kiwisimon

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Dec 14, 2006
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#9
Bartek, take the parts back to the bike shop and explain the problem, might be a good time to form a relationship with the LBS so they know you and your bike. I know it's a PITA but a good lesson learnt here about measuring twice before cutting or spending.
 
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