UKH

Hi UKC biking enthousiasts, 

I've been looking to get into graveling and bikepacking for a while but new bikes are expensive and second-hand modern bikes also, due to a shortage of parts. A friend of mine advised me to look into conversions and after a couple of days of browsing I found a beautifully converted 90s (I think, it might even be older) Specialized Hardrock. I bought it for a very reasonable price.

Almost all the parts that matter have been replaced with new or almost new ones and the frame is in good condition aside from some blemishes. The saddle is a bit worn and the pedals need replacement but that's easy.

There is only one essential part that soon needs replacement: the front sprocket. Now, I'd love to keep the original crank and only replace the blade but I'm a bit overwhelmed by all the options. It's currently set up as a 1x9sp and I'd love to keep it that way for now so I think I need about a 50-54t blade? It has five mount points and as I understand that's a bit oldschool but you can still get them.

My main question is this: how do I go about selecting a fitting blade? Obviously I'm going to visit my local bike shop as well to see what they say but I'd love your input as well!

Thanks

Hi,

You'll need the BCD (Bolt Circle Diameter) of the chain wheel. Then pick the one with the right number of teeth.

https://www.wolftoothcomponents.com/pages/how-to-measure-bolt-circle-diamet...

Mark

Ah great, thanks! I should have a calliper laying around somewhere... 

50-54T sounds like a very high gear for off road. How many teeth on largest sprocket on the cassette on back wheel?

Make sure you get a narrow-wide chainring aka single speed ring.

Thanks for your input guys. The original ring has 42 embossed on it so I think that is the number of teeth I should go for. 

I just visited my local road/gravel shop and had them have a look. 

The upside: the chainring is far from shot, it actually looks almost brand new. I wasn't familiar with the concept of shortened teeth so I thought they were worn. 

The downside: it's a bit of a weird size so when the time comes I might have to replace the  entire crank set with something more modern. But we'll cross that bridge when we get there. 

I have another question for the bike mechanics among you. I've been riding it a couple of days and so far it's been a blast. I haven't been using my smallest or my biggest gears in the back a lot (if even at all) but I can still get it up to about 30-35 kph without ruining my endurance. 

I was looking at replacement crank sets but given that it's a square taper bottom bracket I might be a bit limited. Shimano still makes a couple of 2x or 3x cranks and I guess I could just remove the chainrings I don't need. Then there's the above. It's currently set up with a 42t chainring but given I barely use the smallest gear I guess I could go down a couple of teeth? Let's say 36 or 38? Or would that be too low? I live in Holland so it's mostly flat but in the future I do want to use it for bikepacking abroad. 

Do any of you have any experience with smaller brand 1x cranks? 

In addition to this, the 9sp cassette in the back is 40-11. 

40 and 11 sprockets may be useful for going up/down hills. If you are using mostly middle gears that indicates the gearing might be about right for you and the terrain.

Idly looking at reviews during lunchtime...

https://www.cyclingnews.com/reviews/3t-exploro-review/

1x gravel bike with 42 chainring and 11-42 t cassette - quite similar gear ratios to yours

Admittedly some are 42 chainring with 10-50 t cassette, 11 or 12 speed and bl##dy expensive!

Thanks, I've started looking for a square taper narrow wide crank. So far FSA Vero Pro 1x is the biggest contender as it's an all-in-one package whereas most Shimano cranks would require me to tear off the chainrings and replace it with something else.