JamesRL

I'm a older Clyde, getting back into cycling and not yet in great shape.

I bought an old beater, a 1990 Trek 330. It was a bit of a frankenbike, but its tuned and rideable with upgraded wheels.

It was a six speed bike with Shimano light action, but a 7 speed freewheel is on the newer rear wheel (14-28). It shifts ok but occasionally a hestitation or skip.

I'd like a lower gear. Yes, I should be able to handle it with that wide a range, but I'm not there yet, and I may not get there.

I've been looking at compact cranksets, and it would seem to be a better solution than trying a triple.

But I've seen compatibility statements about compact cranksets online, saying they are 9 or 10 or 11 speed compatible.

Any issues using one of those with a 7 speed freewheel in back?

HillRider

There won't be any problems with the 7-speed freewheel but the wider chain may cause shifting problems with a 9-speed or narrower crank.

JayGK927

Correct me if I am wrong but I believe you need to double check the derailleur capacity. The derailleur capacity dictates whether you would need a long cage or short cage rear derailleur. It is pretty easy to calculate to make sure you won't need to replace the rear derailleur.

JamesRL

Well I can take it to my local bike shop, but I prefer to do my homework first.


Here is my model of Derailleur, from my model's description in the old catalogue it is a light action, but as a frankenbike, it could be anything, as all it says is Shimano SIS. So I am having a challenge finding the max capacity online. Can't find this exact one in Velobase or Disreali Gears.

Drew Eckhardt 

They're not, unless you're the company making bikes (or bike parts) and the compact crank lets you sell fewer SKUs.

24x28 (the smallest chain ring you can get on a 130/74mm BCD road triple) is like 34x40 which is impractically large.

Where similar ranges are possible the road triple will give you gears that are closer together and mean less front shifting.

You might have to space out one of the chain rings to avoid rub with the wider chain. LeTour makes very thin (0.6mm) spacers for the 9 to 10 speed conversion, and there are more sources for wider (1mm) spacers.

Andrew R Stewart 

I agree with Drew's take on this. The whole move to compact gearing is so riders don't have to learn how to shift with thought and skill. The "new" (actually been done way before) 1x10(11) systems are a further extension of this movement.

Being a retro type i feel that every rider should not be allowed to use SIS shifting, ramped rings, HG type cogs for a number of miles/years. Like learning to drive with a manual transmission car. This way every one will need to learn how to soft pedal at the moment of the shift and not depend on an app to do the skilled stuff for them. Andy.

JamesRL

I'm not sure I need a total granny gear, I would think the difference between a 52/42 and a 50/34 would be significant for me. I don't have mountains around here, but there are some hills.

bobotech

I see where Drew is going with this. If you had a 10 or 11 speed system, it wouldn't be as much of a deal. You would have a wide variety of rear gears to give you more choices. You only have 7 gears so you don't have the wide variety of gears to choose from.

The problem is that sure the 34 would be easier than the 42 but you lose the 42. My main bike is a 50-39-28 triple. My other bikes are usually 52-42-28. With that said, I generally keep my front gear in the middle ring (39 or 42) and only shift out to the 50 or 52 when descending a good sized hill or shift in to the 28 when going up trouble hills.

If I only had a 34, I would be running out of gears to shift to and being forced to shift to the 52 which would then require shifting the rear back down. Going to a triple allows you to keep your 42 which you probably stay in 90 percent of the time but gives you the bail out gear needed for hills and you still have your descending gears.

I'm also a large clyde which means triples are much easier for me.

JamesRL

Well I hate to tell you Andy, but I have put more miles on non SIS bike than SIS ones. Mind you it was in the 70s and 80s. I actually toured with a rack, panniers and handlebar bag on week long solo tours on a bike that had 10 speeds. (2 x5) And that trip included some mountains. At that point I had two bikes, one for touring and a racer for fun. Neither of those were indexed.

And I can in fact drive a manual car.

For me the move to compact isn't to shift less or more, it is to have a wider range for the hills. I do realize that many of my peers are driving hybrids with triples, but that might mean a whole new bike would be the better option. I'd rather see if I can make this bike work for me, because in the other ways, it fits well.

bobotech

The problem is that you lose the center range. You have to realize that you lose all those gears in the 42t range when you go to the 34 and so you will have to shift back and forth the front chainring probably quite a bit more frequently than you do now. My small ring is a bailout only for tough hills so I only use it once in a while.

hueyhoolihan

i would just look at getting a different chainring or two and/or a new cassette. should minimize DR issues.

zukahn1 

A basic modern compact double and 7 speed freewheel should work fine with a nicer 8 or 9 speed chain and likely be fine with the current component if there in good shape.

rccardr 

^This.
You'd be surprised at how much flexibility you'd have with a compact crank and wide range cogs. Your RD will accept up to 28 according to Shimano, but mine works well up to 32 in friction. A 34/32 combo is pretty easy on most hills, but even a 34/28 is great unless you have super steep hills to deal with.

Rule of thumb: use a chain that matches the highest number of gears in. Your combo. So with a 9/10 speed crank, use a 9/10 speed chain. Works fine.

JamesRL

When I say I'm a Clyde, I'm a 220 lbs 6' guy. Realistically I'd like to be down to 200. I am still able to spin a pretty fast cadence and I can stand if I need to.

So while hills are a challenge during the first part of the season, my fitness will improve. I went to one of the gear calculators and compared the two setups, and I think the compact will do it for me.

fietsbob

Compact IE a 110 bolt circle crank is an old design .. any thing from 34t upward would bolt up ..

past 8 the chain had to get thinner, to pack in more speeds. so the spread between the chainrings thinned ,as well ..

jforman

Perhaps you could just change the chain wheels to a 50/34 combination, or as I've done 46/34. I still use an 8 speed chain and the same crank that are on the original bicycle. I believe you can get a seven speed back cog 13-28 also. This will give you a wider range of gears.

(Yes I also own triple front chain wheel bicycle and yes I have to mentally divide the compact double into an upper range and an over lapping lower range. When I approach a hill I have learned to shift to the 30 chain wheel and immediately afterwords up shift my back cog set to approximate a similar gear ratio. But then I use to double clutch my TR-7 to down shift.)

I feel that you should do what you want cause you'll never satisfy everyone.

Andrew R Stewart 

James- i am glad that for you my comments about shifting skills don't apply. Oh how i wish that this was the case for the thousands of other riders. With your experience you should know the options you have and their gearing results. As they say 'do the math'. The compatibility concerns with 7 speed rear cog sets and the chains usually used with such and the, usually, intended 9/10/11 speed cranksets can be played with by using Drew's suggestions of chainring bolt spacers. This potential solution has been used for many (as in decades) of years before "compact" was a marketing term.

I am also glad that you are strong enough to not need the gear range that a triple crank can offer. I am not. I once thought I was (loaded touring through thr Finger Lakes on sew ups and a 42/52x14/28 5 speed freewheels bike) but my knees say otherwise now a days.

When i started out in this business there were touring set ups with 36/50 and 14/28 5 speed freewheels. But no one called then "compact". We just called them the gearing the riders needed. Like so many ideas that were actually pretty good BITD they are being rehashed, but with new catch phrases to appeal to the masses.

The reference to learning to drive a manual transmission car was only to make a point that we are a society that is expecting less basic knowledge from drivers and are relying more and more on the decisions of others to keep us on the road. Another example of this is the assumption that 4 wheel drive (oh, I mean "all wheel drive") will let drivers not crash or slide out of sloppy/snow covered roads.

As i have said many times before, my posts are often more for the other readers then directed at the OPs. If i had a beef with you i would have used your name and been even more direct. Again sorry if i ruffled your feathers. Andy.

krobinson103

I swapped out the road group 8 speed on my 2300 groupset with an altus 11-34 megarange cassette. Took some adjusting but the derailler with a slightly shorter chain (tension is ok not great but it works) actually works! with 53-39 up front and 11-34 at the back I have enough range to climb a steep hill but still go fast on the flat. Spaced out the gears a bit compared to tourer running 9 speed deore 12-32 with a 28-38-49 triple but it beats the heck out of 39-25 as the lowest knee destroying gear. No problems with fitness or muscles but my knees can't take the stress.