Straddle Wire

[cooper_coleraine]

I bought a Suntour heavy grade straddle wire for my Shimano cantilevers. Unfortunately it is too thick to pass through the eyelets. This was a mistake due to my ignorance. Those who need to can learn from my mistake.

[gaz]

Which Shimano cantis?

It's fine with my BR-M732 / BR-MT60 / BR-MT62

[Brucey]

I've never had a problem fitting quite thick cables through shimano canti pinch bolts either.

Mafac cantis used skinny straddle cables, but I can't think of any others offhand...

cheers

[Cunobelin]

I used to end up with short lengths of brake cable when replacing them, as the protected part by the lever was OK

These make good straddle cables

[cooper_coleraine]

Thanks for your interest. I cannot find the Canti number but the are the original Shimanos on my 1987 and my 1988 Raleigh Randonneur. There is no way this Suntour wire , bought from SJCycles, will pass through the eyelets.

[gaz]

Possibly BR-AT50, should be on the rear of the brake arm. I have one set lurking somewhere in the shed but it's years since I last had them fitted.

[Brucey]

the brake model number is usually on the back of one of the brake arms. From memory I also think you may have shimano model BR-AT50 on your bike.

This brake originally came with 1.6mm dia straddle wires and the pinch bolt in the arm is drilled to ~2.2mm. I have never seen a cable over 2mm dia used on a bike brake anywhere, so I'd assume that any normal cable ought to fit that pinch bolt OK. Several other shimano cantis made around that time use a similar pinch bolt design.

Have you moved the backing washer away from the pinch bolt to give a clear run into the hole? Is the pinch bolt in good condition? Have you actually measured the cable or the hole diameter?

BTW apologies if this is b-obvious, but if you trim the cable to length, or the cable end isn't well prepared for some reason, you may well struggle to get it through a hole of any kind; a slightly frayed cable end can be considerably larger than the nominal cable diameter.

cheers

[gaz]

The Suntour straddles are visibly "chunky" my vernier gauge puts them in the region of 2mm*. More importantly I can confirm that it does not fit through the pinch bolt eyelet on an AT50.

Edit Spoke too soon, it does fit.


*It's a cheap and somewhat abused manual gauge, it doesn't do accuracy.

[cooper_coleraine]

Gaz is right the Suntour straddle wire does fit the eyelet on the AT50. Earlier authoritive comments shook my confidence so I took the bike and straddle wire to a respected cycle mechanic who confirmed that it does not fit. I now need my confidence restored on my Tange headset query !

[Brucey]

this is the straddle in question;



which looks to be what I would describe as a 'braided' cable. If so this cable type retains flexibility despite its relatively large diameter. I have fitted similar braided cable to BR-AT50 pinch bolts. The cable I fitted measures 2.0mm OD. It will only go through the pinch bolt if every single strand is in place.

BTW I rechecked my pinch bolt measurements and I consistently got measurements between 2.2 and 2.3mm (BTW the pinch bolt in the yoke has a hole that is slightly larger than that). The threaded end of a 14G spoke (which measures 2.25mm) will go into the pinch bolt hole one way but not the other, indicating that there is probably a small burr at one end of the hole. [Another spoke thread which measures 2.17mm goes through OK] If the Suntour cable does not go through the hole there are only three reasons

1) the cable is bigger than that
2) the hole is smaller/needs deburring
3) the end of the cable is slightly mangled in some way.

I'm interested to know which of the above it really is because I had planned to fit some of these straddles myself. If it is just a question of deburring the hole in the pinch bolt or dressing the end weld on the cable or something like that then I think that would be easy enough to do.

BTW they sell nice quality digital vernier calipers in ALDI for about ten quid. These are incredibly useful when 'stuff doesn't fit' because you can very quickly work out where the problem is. So much better than just guessing...

cheers

[gaz]

... If the Suntour cable does not go through the hole there are only three reasons

1) the cable is bigger than that
2) the hole is smaller/needs deburring
3) the end of the cable is slightly mangled in some way.

I'm interested to know which of the above it really is because I had planned to fit some of these straddles myself.

I'll have a little play around tomorrow. A new vernier gauge is already on the wish list, just waiting to see one on the shelf when I'm in Aldi.

[JakobW]

Lidl are doing digital verniers this week, at least round my parts - I just picked up a pair...

[gaz]

Thanks for the heads up. Bike stuff on Monday too.

[Brucey]

I'll have a little play around tomorrow....

much appreciated!

cheers

[gaz]

If at first you don't succeed ...

DSCN0161.JPG

Just keep listening to Brucey .

I did a bit of deburring with a narrow file, then tried again with a new cable fresh out of the packet. It didn't work.

Then I tried another cable, one that I'd previously cut shorter. It fit. So I tried a couple more uncut ones, they fit as well.

The first cable still doesn't fit, I'd guess the end weld needs dressing. Still three out of four isn't bad .