Australian Cycling Forums - Bicycles Network Australia

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:



Here's the dropbolt:

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

And here's the reach issue:



Thanks in anticipation.

Mark

Or something like...

https://www.bdopcycling.com/BDop%20Offset%20Holders.asp

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.

Sheldon once wrote about how to DIY them



(All images from Sheldon Brown and John Allen)

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

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.

090 by Derny Driver, on Flickr

Derny Driver wrote:090 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!

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

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.

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.

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).

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.

021 by Derny Driver, on Flickr

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

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

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

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

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 cranks)

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 cranks)

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

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

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.

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!

Mental note: Don't buy a bike from Derny Driver.

Those offset pad holders look good... probably the neatest solution if you want to keep the same caliper.

Well I got the BDOP offset pad holders and they were the perfect solution.

Photos etc can be seen over here at the thread I've been running about the restoration of my bike: http://www.bicycles.net.au/forums/viewt ... 23&t=78436

Thanks for all the help! Mucho appreciated!