Shimano SIS-SP 5mm Gear Cable

Hello RetroBIKErs!

I'm in the middle of restoring my 1994 spec GT TIMBERLINE and have decided that I need to replace both the brake and gear cables. The housing is pretty shot on both with the plastic cover split and worn here and there. The cables are also very dull, almost rusty, where they are exposed along the run on the underside of the frame.

Finding new brake cables doesn't seem to be a problem. There are several different ready-made sets that have 5mm casing with 1.6mm cable, and as far as I can see, there's no difference between road and MTB sets other than different pre-cut lengths of inner and outer cables.

But, not so easy for the gears. The bike was originally fitted with SIS-SP cables which has 1.2mm inner and 5mm outer. The casing is noticeably stiffer than the brake casing so I don't think I can use that. But I can't seem to find anywhere in the UK that stocks SIS-SP - it all seems to be SP-41 which has a 4mm casing.

I'm sure the SP-41 stuff is up to the job and it's only 1mm difference but the receptacles on shifters and frame are all sized for 5mm (actually 6mm for the ferules).

Any help or pointers greatly appreciated!

I'm really going to town on this one as believe it or not this is the first time I've done any maintenance on my bike in 23 years!


Brand new 11-28t Shimano HYPERGLIDE-C cassette with new spoke protector


Restored Araya AP-21 26" wheels with Schwalbe RAPID ROB tyres


Polished Shimano Alivio Upgrade Edition HyperDrive-C, 24/34/42t crankset


GT logo on headtube after frame was re-sprayed with automotive clear lacquer


New Shimano sealed bottom bracket

As you're not keeping it original, just use any old cable, it'll all work the same.

Re:

After some intensive Googling I managed to find a shop in the UK that has stock of Shimano SP51 Gear Casing, which appears to be the correct match for the SIS-SP that was fitted originally. It's the extra stiff stuff for gearing.

http://www.jejamescycles.co.uk/shimano- ... d6060.html

Sold by the metre, currently £3.59.

Tarty Bikes also seem to have it too:

http://www.tartybikes.co.uk/rim_brake_s ... 11637.html
£6.00 for 1.5m + 2 ferrules

Cool, thought this stuff had all but disappeared. Might have to get myself a few spare metres

Re:

My_Teenage_Self":zvbf8kr6 said:

As you're not keeping it original, just use any old cable, it'll all work the same.

Click to expand...

Keeping it pretty original! I ditched the original one-piece cow-horn handlebars not long after I got it 23 years ago after a little accident where they got wrapped around a small tree (!), but almost everything else is as it was. I managed to source a NOS Shimano HYPERGLIDE-C 7-speed 11-28t cassette and matching HG50 chain, all the brake and gear cables will be authentic Shimano spares, the new bottom bracket is a Shimano BB-UN55 that's a better spec than the original Shimano BB-LP30.

I've had to concede to a non-authentic seatpost as I've "misplaced" the original. About 15 years ago I switched to a ZOOM suspension post when I did a London to Brighton off-road charity ride. Eventually it got jammed in the frame as over the years the aluminium corroded. To remove it I had to dissolve it in repeated baths of Sodium Hydroxide (Caustic Soda) - a nasty and messy job! The new seat post is a Brand-X Inline 6061. The clamp design looks just like the ALL TERRA posts used on many current GT models, so looks the part as I managed to get hold of a brand new GT saddle from a bike shop that had removed it unused from a new bike!





Obviously after 23 years the TIOGA PSYCHO-II tyres were way past their best! Whilst there was still plenty of tread the rubber was really starting to decay, so no choice but to get something new. Again, as a nod to the current GT bikes, I went with a set of SCHWALBE RAPID ROB 26 x 2.1 tyres as GT fit Racing Ralphs to several current trail models, although they're probably the fancy Evolution Folding SnakeSkins and not the standard K-Guard Active Line! Tyre choices are limited for 26" wheels in a fairly narrow frame - the original PSYCHO-IIs were only 26 x 1.95 so I couldn't go much wider.

All-in-all it's not going to look too dissimilar from the day I bought it and I think it'll be as sweet a ride as ever!