SIS front crankset replacement..(90s taper-axle hybrid bike)

DxMachina

Dirt Disciple
Hiya

Posting this here despite the bike pre-dating 1998 as I'm open to modern suggestions and not doing a classic restoration per se....

Recently purchased a pair of mint condition 1990s Raleigh Pioneer Classic hybrids after my wife expressed an interest in riding with me (she hadn't ridden a bike in 30 years). She's loving hers (SIS 5-speed 1992 model) but it's definitely too high-geared for her - has a regular SIS 5 speed rear cassette and a single front crankset of about 44/46 teeth (by appearance, havent counted them yet)

Being a SIS multispeed model it takes a narrow 3/32 chain. The gearing on my 10-speed SIS gents bike is about right for her if the smaller front gear is selected (36 or 38 tooth?) as she's never yet gone above 3rd gear on hers and finds 1st too high-geared (Understandably, it's comparable to about 11th on a 15-speed MTB). So obviously I need to find a smaller front crankset for a narrow chain, OR a multispeed front crankset and just fit it with the chain on the smaller chainring.

Does anyone know if original Raleigh or compatible front chainrings for narrow chains (on a typical 1990s square tapered axle) are generally available? Or could I find a multispeed one thats modular and remove some of the unnecessary chainrings?

Online searches predictably find a huge range of cranksets that are suitable for my 1980s Triumph singlespeed (eg 1/8th chains) and not much for SIS-compatible ones...

Ideally, although not necessarily, any replacement front crankset would have a plastic guard-ring on it like the original one does.

Thanks in advance for any advice
Chris
 

hamster

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RIngs should be easily available. Try Spa cycles. For light duty the Stronglight Dural ones are good value.
 

legrandefromage

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The Pioneer had a sort of one piece crank/ guard assembly any good single speed chainset should go in its place without the need to even change the BB axle

*make sure the chainring is suitable for multispeed otherwise the teeth may be spaced for the larger chain used for single speeds

I'm sure the Pioneers were 6spd too

Vintage-1990-Large-Mens-White-Raleigh-Pioneer-Presitge.jpg
 

DxMachina

Dirt Disciple
Thanks. I've done some more looking at the 2 bikes now. While both have the same 5speed rear wheel and rear derailleur the front cranksets differ.

The 10-speed has removable rings and chainset bolts. The 5 speed has a one piece crank-chainring (square taper), as you say above - so I need to remove the crank and replace it with a smaller one.

Both have a 5speed rear cassette which is staying. So using a singlespeed crank generally isn't possible as they are usually built for 1/8th-width singlespeed chains, while this has to be compatible with a 3/32 multispeed chain due to having a rear derailleur.

I am guessing my best bet is to find a used MTB shimano triple crankset from the 90s and remove the larger and smaller chainrings from it?
 

legrandefromage

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Or use a single speed crankset with a normal ring on it?

In my bin of parts I have a Suntour single speed chainset with a chain guard, it is running a small Middleburn ring at the moment.

Do you have any pics of the bike? That can help with all sorts
 

DxMachina

Dirt Disciple
OK, thats a possibility I wasn't aware of. The only s/speed cranksets I'm familiar with are the type on my Triumph (per profile pic) - which is single-piece. So I can get a s/s crank with removable chainring, remove it from the crank spider and put a narrower chainring on?
 
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