Gear Ratios

[Catatonic_Joe]

Hey guys,

 

So I recently purchased an 0ld Bridgstone RB-2 (1988) Road Bike to use for commuting and will probably use it for 94.7 and any other road races I feel like doing, My other bike is a Giant Anthem that I used to commute with but now only use it to MTB on weekends and I regularly enter MTB races.

 

Problem is, I'm struggling to climb on the Bridgstone, my commute to work is just abut 10km's, and quite a bit of climbing, I find I'm getting to the lowest gear quite quickly, especially on the really steep ones. I'm trying to push myself to ride in harder gears on the not too steep climbs to hopefully build my strength, but I'm worried about the 94.7 and how I'm going climb those last hills at the end after already doing 80km's.

 

Also, I found that I'm finding it hard to beat my Strava efforts   up hills on the Bridgstone that I've got on my Anthem. I initially though it was a no brainer that I would be quicker on the road bike than on my MTB, but I keep getting better times on the MTB up the same hills.

 

The ratios on the Brigdestone are 52/42 in the front and the cassette is a 6 Speed 13/26.

 

I'm not much of a roadie so I would appreciate some advice on what I could do on a limited budget (awaiting arrival on second child) on how I could make the Bridgestone easier to ride.

[raptor-22]

Compact crank and new bb

[PJP2013]

Hi

 

The 42 is causing your problem. If you can find an old 36 or 39 tooth small chain ring it should sort it out.

Edited October 28, 2015 by PJP2013

[Brickleberry]

Going from MTB to road I also struggled in the beginning. a 42 small ring up front is what's killing you I think. My std 53/39 is tough enough on really steep hills. I also agree you should look out for a compact crank however I'm not sure you will find one that fits a 6 speed. (More knowledgable people can help there). But as your legs get stronger you will turn the gear more efficiently and then you will fly.

[PJP2013]

Compact crank and new bb

 Budget solution?

Edited October 28, 2015 by PJP2013

[Catatonic_Joe]

Thank guys

 

The 42 is causing your problem. If you can find an old 36 or 39 tooth small chain ring it should sort it out.

 

Thanks PJP2013, I fear it might be a bit more complicated though, the bike is original and came with Biopace chainrings... I assume I would probably need to replace both chainrings for it to work properly, unless I find a 39 Biopace chainring. Would it be possible to get both standard 42 and 39 chainrings and replace them on the current crank, or would I need a whole new crank?

 

The crank is a Shimano A450

[raptor-22]

Good luck finding a 39t bio pace chainring.

An 8 or 9 speed compact chain set will work. Shimano makes good quality budget chainset in sora and lower.

Explore that on chain reaction cycles. I don't have much faith in the local shimano agent to sort you out. Maybe they will surprise

[s14phoenix]

swapping between my road bike and mtb, the mtb does feel like the brakes are on.

 

However if your cadence is not in your comfort or most comfortable zone then you will battle.

 

if you can stay around the 80s you should be ok.

 

I have seen guys with 50/34 cranks and 11-36 10sp mtb cassettes passing some "purists" making them look silly... and that's on the hills and flats and downhills...

 

Don't fool yourself about doing it the "right" way. You only fooling yourself. I would swop out that crank to ease the ratios. 50 - 11 drive can still do 70kmh and more if you can rev the engines a bit...

[PJP2013]

Thank guys

 

 

Thanks PJP2013, I fear it might be a bit more complicated though, the bike is original and came with Biopace chainrings... I assume I would probably need to replace both chainrings for it to work properly, unless I find a 39 Biopace chainring. Would it be possible to get both standard 42 and 39 chainrings and replace them on the current crank, or would I need a whole new crank?

 

The crank is a Shimano A450

 

Hi, am not an expert on the subject but in those days parts were pretty interchangeable. Best to check with your LBS. Also some bike stores keep old parts, some digging and you might find something that works.

[raptor-22]

Shimano has not changed its bolt circle diameter but chain lines have altered and chain ring thickness has increased. You can fit std round rings that conform to shimano old 5arm spider standard.

You may need to modify the chain ring pinch bolts

[FC&P2C]

Not sure I understand the problem as a 42/26 is as light a gear you will find on a road bike. In the 90's most bikes had a 42/21 as a smallest gear and today 39/25. Your 42/26 is only 3% heavier than the 39/25 but still 5% lighter than a 39/23 that most people are riding today.