6

A while ago I bought a fairly cheap bike - a Pinnacle Lithium 1 from Evans Cycles in the UK. It's dangerously close to being a BSO, but I really enjoy riding it and have no regrets about buying it.

Well, almost no regrets because I find the gears are rather low. Top gear (of seven) is usable (just) on a straight flat road so when there's a steep downhill I run out of gears and have to coast, and I have yet to find a hill so steep I need to use the lowest gear to climb it. It would be nice if I could shift all the gears one place and sacrifice the unnecessary lowest gear for an extra top gear.

The obvious way to do this would be to increase the size of the chainring. It currently has a single 40 tooth chainring, and if I could fit a 46 tooth chainring this would make the gear ratios ideal for me. On a cheap bike I would generally regard this as too much work because the chainring and pedals are a single piece and it would require major dismantling. However it looks to me as with this bike the chainring is on a spline:

Chainring on spline

If so, hopefully it would be fairly easy to swap the chainring. So my question is whether you can tell from the picture whether the chainring is easily swappable, and if so is there a name for this specific type of chainring I could Google to find a supplier?

Update

I was able to pry off the plastic cover to reveal what the pedal side of the chainring looks like:

Chainring pedal side

The chainring does appear to be separate from the pedal, so I suspect if I take the pedal off the chainring will slide off the spline as well.

4
  • If you undo that Phillips head screw on the spider, does that begin to release the chain ring cover? If so, that could provide a bit of an additional clue.
    – FreeMan
    Aug 31, 2021 at 17:14
  • 1
    I think those screws just hold on a plastic guard that shields your trousers from the teeth. I suspect to get the plastic cover off I'd have to remove the pedal-arm/crank Aug 31, 2021 at 17:16
  • 3
    @JohnRennie: I suppose that you could just slip the guard ring over the crank & pedals. That's also the way I move both Shimano (Ultegra or 105) rings over the crank. There's generally no need to remove crank or pedal.
    – Carel
    Aug 31, 2021 at 17:34
  • 1
    I used to have a crank with similar looking chainring. It was not easily removeable and I haven't seen spares with similar interface. It certainly looks like SRAM direct mount chainrings, but those have clearly visible bolts. There are lots of singlespeed square taper cranks made to be used in fixies, they should work in your bike too.
    – ojs
    Sep 1, 2021 at 8:15

2 Answers 2

4

I had a quick look on the specs of the bike:

  • the specs don't give any useful info to choose a new chainring, so I would assume it cannot be changed (except by replacing the whole crankset).
  • the bottom bracket has a 73mm width, which will limit you to MTB or trekking cranksets (and you will need to change the bottom bracket). It's hard to find MTB chainrings that are bigger than 36 tooth (what you already have, they exist, but with the current supply situation, sourcing one is even more challenging than finding a reference). If you find one, it will for 10-speeds chains or more. Trekking components are excluded because there are only triple chainrings.
  • the cassette is a 14/34 with a freewheel. If you want to increase your top speed, changing the wheel and cassette would also be an option. Free wheels are limited to 14-tooth small sprockets, using a hub with a freebody would allow you to have a cassette with 11-speed sprocket (such a wheel costs 45€+15€ for the cassette). Technically, changing the hub should be sufficient, but at this price point, replacing the hub will cost more than a new wheel (labour+hub+probably spokes). The only 7-speed cassette I found was an Acera 11/28, which seems to match your requirements of increasing your top speed and your low speed. This cassette also matches the specs of your derailleur, so you can keep using it (adjusting the distance to the cassette would be needed though).
1
  • 2
    Thanks, yes I suspect there is no easy way to do this and I just have to live with the existing gear ratios or spend more money than is justified for a cheap bicycle. If it were a major issue (it isn't) then I should put the money towards buying a better bicycle instead. Sep 1, 2021 at 7:00
12
+100

For the record I'll add an answer describing what I did and how it worked out.

Like most entry level bicycles mine uses a square taper crank and there are thousands of square taper cranks available. I bought a Prowheel Zephyr single speed crank and a Deckas 44T narrow-wide chainring for about £30 in total. Changing the crankset seemed intimidating to me as a beginner but it's actually very easy. You will need a crank removal tool, but these are widely available and very cheap. There are plenty of videos on YouTube explaining how to change the crank and in the end I had no trouble doing it.

And I'm very pleased with the final result. I selected a 44T chainring because it effectively moves all the gears up by one i.e. the original 7th gear ratio is now the 6th gear ratio and I get a new higher 7th gear for the faster downhills.

The final cost was about 15% of the cost of the bicycle including buying all tools I needed. Whether this was a good investment will be a matter of opinion, but I am very pleased with the result. I like the bicycle even though it is entry level and now it has exactly the gear ratios I want, and selecting and changing the crankset was a lot of fun and it taught me a lot about bikes.

This is the new crankset and chainring. I initially didn't post a picture because I'm a little ashamed of how dirty the bike has got, but then this is a bike that's used every day and in all weathers. It is a high resolution picture so click on it to see all the fine detail.

New chainring

1
  • 6
    Tools are for life - your next bike fix will be effectively cheaper because you bought some tools now. Downside, there's always more tools to buy.....
    – Criggie
    Oct 16, 2023 at 18:25

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.