Installing a larger chainring

alig said:

Hi all

I have a progear hybrid, I would like to replace the 48T chainring with a 53T (and I'm planning to replace the wheels and tires with 700x28).

I'm hoping to do it myself, and I guess I need to start by purchasing a chainring
Firstly sorry if I come accross as having no idea, because I basically don't and that's why I'm planning to do the work myself so I can get a bit of confidence in doing upgrades

Firstly, are chainring fittings standard? my chainring has 5 holes that connects it to the crank arm. Does that mean any 53T chainring with 5 holes will fit the same crank arm (ie. is the configuration, size and spacing of the 5 holes on this type of chainring the same?)

There are a couple of issues.

First, chainrings are not standard. There are many 5 bolt cranks with different chainring bolt diameters. Essentuially measure from the center of one of the crank bolts to the center of the crank and double that. If it's 65mm, it's a 130mm BCD, if it's 55mm, it's a 110mm, etc.

Second issue is that you need to raise your front derailleur for the new bigger chainring and the resulting differences between the middle ring and the new bigger ring may make for some poor shifting. True also for going to and from the smallest ring since the front deraileur is much higher(assuming here you have a triple, 3 ring crankset). You may need a new FD, then there are going to be issues with shifter and FD compatibility.

So, it's not just a plug and play. I suggest seeing a good, competent bike shop with somebody that understands front derailleurs( one of the more picky things on a bike) and asking if it'll work, and how and see if they will explain what they are doing when they do it.

alig said:

I have a progear hybrid, I would like to replace the 48T chainring with a 53T (and I'm planning to replace the wheels and tires with 700x28).

I'm hoping to do it myself, and I guess I need to start by purchasing a chainring
Firstly sorry if I come accross as having no idea, because I basically don't and that's why I'm planning to do the work myself so I can get a bit of confidence in doing upgrades

Firstly, are chainring fittings standard? my chainring has 5 holes that connects it to the crank arm. Does that mean any 53T chainring with 5 holes will fit the same crank arm (ie. is the configuration, size and spacing of the 5 holes on this type of chainring the same?)

FWIW. It would probably be easier & less expensive to either change the cassette (or, simply the smallest one-or-two cogs) ... or, if necessary, the rear hub (if your rear wheel has a freewheel instead of a cassette) or the rear wheel, itself, plus a new cassette.

I'm going to guess that your bike's rear wheel does not have an 11t smallest cog ... perhaps, the smallest cog is only 13t. If so, an 11-32 LX cassette should cost less than $50 from your local bike shop & give you the gearing you probably want.

A new Shimano hub + cassette + spoke wrench should cost less than $100 ... some shops have *used* (often removed from new bikes) wheelsets which use a cassette which should be suitable for under $100.

BTW. The crankset on many-if-not-most hybrids is often very low end (to keep the cost of the bike under a certain price level), and many do not have replaceable chainrings (i.e., they are riveted to the crank's spider). Sometimes, the rivets can be removed (drilled out) & replaced with chainring bolts, but the cost of your time + parts is often more than the cost of an inexpensive crankset which has replaceable chainrings.

Thanks for the advice. I was wondering what the heck BCD meant when shopping around for chainrings online

I was planning on removing (disabling) the front derailleur anyway, and I thought I'd need to add a few links to the chain.

As for the rear cassette, its an 11-35 (on the current wheel), but I think an 11-25 (or 12-25) on the wheel I'm replacing it with.

Is it worth all the trouble to go from 48-53T anyway?

alig said:

Thanks for the advice. I was wondering what the heck BCD meant when shopping around for chainrings online

I was planning on removing (disabling) the front derailleur anyway, and I thought I'd need to add a few links to the chain.

As for the rear cassette, its an 11-35 (on the current wheel), but I think an 11-25 (or 12-25) on the wheel I'm replacing it with.

Is it worth all the trouble to go from 48-53T anyway?

Proper gearing is subjective and if the new ring works well, shifts well and makes your riding better, makes you more apt to ride, then I think it is worth it.

alig said:

Thanks for the advice. I was wondering what the heck BCD meant when shopping around for chainrings online

I was planning on removing (disabling) the front derailleur anyway, and I thought I'd need to add a few links to the chain.

As for the rear cassette, its an 11-35 (on the current wheel), but I think an 11-25 (or 12-25) on the wheel I'm replacing it with.

Is it worth all the trouble to go from 48-53T anyway?

IMO, for most people & most riding situations, it is probably NOT worth going from 48-53T from EITHER a mechanical OR economic point of view ... UNLESS, you are a really strong rider who lives in a fairly hilly area & want to maximize your overall speed on the downhill portions AND you are already NOT using the middle or inner chainring.

I'm actually a big fan of Hybrid bikes (well, more correctly stated, I'm a big fan of Hybrid frames) for anyone who isn't racing because they can accommodate almost any tyre size + fenders (if desired by the rider) ...

But, if you want to go FASTER, then (after you change the tyres) you are better off changing the handlebars to ROAD-type handlebars (vs. changing the chainrings) because wind resistance is a large factor in determining how fast you can ultimately ride.

Unfortunately, the suspension fork which is more common than not on Hybrids, introduces dead weight & I would actually consider replacing the suspension fork with a "solid" fork at some point in the future if you want to enhance-or-extract the potential maximum performance which the frame will allow ... maybe, not.

If you add up the cost of all the changes you might potentially make, then you may decide that a different bike is warranted because some changes may introduce more expenses than may be worthwhile.

FYI. The rear hub spacing on most Hybrid frames is 135mm ...

Most 700c wheels have 130mm rear spacing unless they where laced/intended for a Hybrid, or modified (i.e., axle substititution).

The OTHER wheel you are planning to install on your bike may have a cassette which is not compatible with your bike's shifters -- possiibly, 9-or-10-speed vs 8-speed.

BTW. MOST Hybrid bikes now come with cranks with 4-arm 104BCD spiders; so, if your Hybrid's crank has a 5-arm spider, it is out of the norm (not that there would be anything wrong with that -- better in some circumstances, worse in others). The only currently available 104BCD chainring larger than 48t that I know of is intended for the new ZIPP crankset, and it is undoubtedly will cost about $100.

If you have an 11-32 (or, 11-34 cassette), I wouldn't bother changing that, either, for the time being. At some point in the future, you may want to use a cassette with less range (e.g., the 12-25 you mentioned) ... but, if you are eliminating the middle & inner chainrings, you may want to continue to use the current cassette because there probably won't be a significant weight saving for the non-competitive rider to warrant the expense.