Fitting a short reach caliper to a 700c wheel

8Track
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Fitting a short reach caliper to a 700c wheel

Postby 8Track » Tue Oct 02, 2018 8:43 am

Hi all,

Just looking for a bit of advice here. I have a Suntour GPX rear brake caliper which is too short to reach my 700c wheel rim.

A couple of suggestions have been made......the best one seems to be to use a Campagnolo drop bolt.

Would anyone know if its possible to remove the stock mounting bolt from my caliper and replace it with the Campag drop bolt?

Here is a pic of my caliper:

Image

Here's the dropbolt:

https://www.ebay.com/bhp/brake-drop-bolt

And here's the reach issue:

Image

Thanks in anticipation.

Mark

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baabaa
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Re: Fitting a short reach caliper to a 700c wheel

Postby baabaa » Tue Oct 02, 2018 9:13 am


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Thoglette
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Re: Fitting a short reach caliper to a 700c wheel

Postby Thoglette » Tue Oct 02, 2018 10:46 am

The correct answer is to get a brake caliper that fits and save your Suntour bling for a frame/wheel combo that fits.

But the NOS campy one looks like it'll do the trick. There were others out there.
Image
Sheldon once wrote about how to DIY them
Image
Image

(All images from Sheldon Brown and John Allen)
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adsjax
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Re: Fitting a short reach caliper to a 700c wheel

Postby adsjax » Tue Oct 02, 2018 8:42 pm

Image
These look like they have an allen key bolt head at the front. If you use the drop bolt and the diameter and thread pitch is the same, you will end up with the end of a threaded bolt sticking out the front which will then need a suitable nut to secure the caliper. It won't look the same and I wouldn't want to be messing around like that with NOS Suntour calipers. Not sure how much you have found the drop bolts for but $60 could get a set of new double pivot calipers like Shimano R451's or Tektro R539's which will perform better

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Derny Driver
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Re: Fitting a short reach caliper to a 700c wheel

Postby Derny Driver » Tue Oct 02, 2018 8:51 pm

Use a hacksaw to cut the metal out so that the slots are longer. File it smooth. Drop the brake blocks right down on the bottom of the slot. When they are in position you cannot see the modification.
I know its hard to take a hacksaw to nice brake calipers. Just do it. They are not an expensive item. Ive done it to Campag Chorus Monoplaner calipers, arguably one of the nicest brakes ever made.

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Derny Driver
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Re: Fitting a short reach caliper to a 700c wheel

Postby Derny Driver » Tue Oct 02, 2018 8:51 pm

Image090 by Derny Driver, on Flickr

BJL
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Re: Fitting a short reach caliper to a 700c wheel

Postby BJL » Wed Oct 03, 2018 12:12 pm

Derny Driver wrote:Image090 by Derny Driver, on Flickr


Ugh!

No! Just NO!

I'd never ride a bike like that where the brake pads could just 'drop out' of a slot like that. I'd rather the limited braking from brake pads rotating in the slots to that. Just nooooooooooooooooooo. But if you would, that's up to you.

As YOU said, calipers aren't that expensive either, in the great scheme of things. Buy the right ones for the bike for gods sake!

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Re: Fitting a short reach caliper to a 700c wheel

Postby NASHIE » Wed Oct 03, 2018 12:51 pm

Can’t say i’m fan of the slot idea either. File slot lower but to break through is real bush mechanics

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Thoglette
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Re: Fitting a short reach caliper to a 700c wheel

Postby Thoglette » Wed Oct 03, 2018 3:12 pm

BJL wrote:I'd never ride a bike like that where the brake pads could just 'drop out' of a slot like that.

My current brakes have at least six single-nuts (at each end) in which looseness would lead to total brake failure.

And that's before I talk about the lawyer-lip free forks.

It is fairly ugly

BJL wrote:Buy the right ones for the bike for gods sake!

Agreed.
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Re: Fitting a short reach caliper to a 700c wheel

Postby piledhigher » Wed Oct 03, 2018 3:30 pm

Thoglette wrote:
BJL wrote:I'd never ride a bike like that where the brake pads could just 'drop out' of a slot like that.

My current brakes have at least six single-nuts (at each end) in which looseness would lead to total brake failure.


Given that the two ends are completely independent systems, it's only a partial brake failure. That said loss of front brake at a critical moment is something to avoid.

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Re: Fitting a short reach caliper to a 700c wheel

Postby 10speedsemiracer » Wed Oct 03, 2018 3:31 pm

As someone who has done the dremel-based caliper slot elongation thing on a couple of occasions, I also couldn't abide the open-ended slot thing, and also feel the need to point out that some of the alternate solutins being considered will all have an effect on braking performance to varying degrees by allowing the potential for flex/movement of the caliper when braking with the potential to diminish braking performance and perhaps even damage the bridge. Also, for the most part, they are less-than-elegant (ugly).

I would think there are some other options, which some have also mentioned, i.e. some long reach calipers like the DiaCompe 55-75mm (is similar to the Tektro r559) or find a friendly frame-builder who'll rebraze the bridge in a lower position on the frame (drastic, but hey, we've all done stuff to make bits work).
Mmm, SunTour

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Re: Fitting a short reach caliper to a 700c wheel

Postby Derny Driver » Wed Oct 03, 2018 4:40 pm

haha I didnt think you'd like it.
For what its worth, all my bikes are show only, I dont ride them. Even so I cant see brake pads just "falling out" if they are done up tight.
I actually had a few problems with this bike. Its an Italian Faggin and I assumed it was a late-ish model frame and started building it with Chorus 8 speed and Campag Vento 700cc wheels. Went to fit the brakes and realised
1. the rear bridge and fork crown are not drilled for recessed bolts. Old style nutted calipers only.
2. the wheels should be 27 inch, not 700cc
So with bush mechanics (Nashie) I got the Chorus calipers on there ... but I must admit Im not entirely happy with the look. At some stage I will remove the 8 speed Chorus gear and replace it with something more ancient, with 27 inch wheels. But for now, I have 5 other bikes Im building so this little job can wait. As I said, its just for show, and hard to pick unless you look really closely.

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Re: Fitting a short reach caliper to a 700c wheel

Postby Derny Driver » Wed Oct 03, 2018 4:44 pm

Image021 by Derny Driver, on Flickr

NASHIE
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Re: Fitting a short reach caliper to a 700c wheel

Postby NASHIE » Wed Oct 03, 2018 4:55 pm

Derny Driver wrote:haha I didnt think you'd like it.
For what its worth, all my bikes are show only, I dont ride them. Even so I cant see brake pads just "falling out" if they are done up tight.
I actually had a few problems with this bike. Its an Italian Faggin and I assumed it was a late-ish model frame and started building it with Chorus 8 speed and Campag Vento 700cc wheels. Went to fit the brakes and realised
1. the rear bridge and fork crown are not drilled for recessed bolts. Old style nutted calipers only.
2. the wheels should be 27 inch, not 700cc
So with bush mechanics (Nashie) I got the Chorus calipers on there ... but I must admit Im not entirely happy with the look. At some stage I will remove the 8 speed Chorus gear and replace it with something more ancient, with 27 inch wheels. But for now, I have 5 other bikes Im building so this little job can wait. As I said, its just for show, and hard to pick unless you look really closely.


Chorus 8 speed is my favourite groupset.......and you butchered it :wink:

I've got a spare set of callipers if you ever want to fit group to a correct frame and ride in anger.

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Thoglette
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Re: Fitting a short reach caliper to a 700c wheel

Postby Thoglette » Wed Oct 03, 2018 5:10 pm

10speedsemiracer wrote:I would think there are some other options, which some have also mentioned, i.e. some long reach calipers like the DiaCompe 55-75mm (is similar to the Tektro r559) or find a friendly frame-builder who'll rebraze the bridge in a lower position on the frame (drastic, but hey, we've all done stuff to make bits work).

There's a crap load of them, from Shimano (e.g. br-r650 ) Tektro (556 or 539) plus others. And that's just side pulls.

Then there's the centre pulls from Mafac, Dia-Compe and Weinmann to Paul, Compass and VeloOrange
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10speedsemiracer
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Re: Fitting a short reach caliper to a 700c wheel

Postby 10speedsemiracer » Wed Oct 03, 2018 5:15 pm

I've used the br-650 on a couple of occasions, very nice calipers, but was trying not to offend the SunTour-ness of the bike by suggesting Shimano calipers....

At least DiaCompe and SunTour have some history together, so sort of appropriate
Mmm, SunTour

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Thoglette
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Re: Fitting a short reach caliper to a 700c wheel

Postby Thoglette » Wed Oct 03, 2018 5:31 pm

10speedsemiracer wrote:I've used the br-650 on a couple of occasions, very nice calipers, but was trying not to offend the SunTour-ness of the bike by suggesting Shimano calipers....

Certainly. :-)

I'm not a SunTour fundi but weren't the SunTour Superbe 47-57mm (a.k.a. medium) reach? A few years too old, perhaps?

It's a shame SunXCD aren't doing brakes but I guess they've picked their patch (I want the rear derailleur and cranksImage)
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Re: Fitting a short reach caliper to a 700c wheel

Postby 10speedsemiracer » Wed Oct 03, 2018 5:56 pm

Thoglette wrote:
10speedsemiracer wrote:I've used the br-650 on a couple of occasions, very nice calipers, but was trying not to offend the SunTour-ness of the bike by suggesting Shimano calipers....

Certainly. :-)

I'm not a SunTour fundi but weren't the SunTour Superbe 47-57mm (a.k.a. medium) reach? A few years too old, perhaps?

It's a shame SunXCD aren't doing brakes but I guess they've picked their patch (I want the rear derailleur and cranksImage)


You're right, the Superbe came in short (39-49) and medium (>57mm) reach. I've just bought some medium reach NOS Superbe Pro calipers and levers from the US (effing expensive) but as you say, are about 5 yrs pre the Elan bike that OP is dealing with.

Agree that is a shame there aren't any SunXCD brakes as yet, fairly sure they'd be awesome, however with DiaCompe having made most of SunTours brakes under license over their last 15 or so years, I'm not sure it matters
Mmm, SunTour

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Derny Driver
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Re: Fitting a short reach caliper to a 700c wheel

Postby Derny Driver » Wed Oct 03, 2018 6:05 pm

NASHIE wrote:
Chorus 8 speed is my favourite groupset.......and you butchered it :wink:

I've got a spare set of callipers if you ever want to fit group to a correct frame and ride in anger.

One of my favourites too. I have it on my Coppi as well. And i have another box with a third 8 speed Chorus groupset waiting for the right frame. Although that set has the skeleton calipers.
Im always after parts if you are looking to sell. At the moment im collecting Galli, Zeus, Stronglight, Superbe Pro and Chorus stuff. Im always after wheels too.

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Re: Fitting a short reach caliper to a 700c wheel

Postby 8Track » Fri Oct 05, 2018 12:51 pm

Thanks everyone! The reason why I'm trying to stick with the GPX calipers is that Ihave doen a restoration on a vintage bike with a NOS GPX groupset. I didn't know the calipers were too short for 700c wheels.

It looks like the offset pad holders are my best bet!

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