Chainring/Chainwheeel Replacement, Old Ross Gran Tour
I've got an old 1981 Ross Gran Tour 10 speed that I've had since it was new and it finally needs the chainrings replaced due to wear. But this bike has a rather strange setup compared to more modern bikes, so I don't know what approach to take... and skip the "get a new bike" advice - I'm keeping it for sentimental reasons.
The bottom bracket on this bike seems to be standard (Hatta brand from what I can make out with the cranks on), square taper axle with bolts that screw in to retain the cranks. Both the cranks and chain rings are aluminum alloy, (Shimano?) Tourney.
Instead of the normal setup with a spider on the crank to hold the large chainring, the chainring (or chainwheel?) seems to ride directly on the axle, being held on by the crank. Looking from the inside, it looks as if there is some type of collar in the center where the chainring meets the axle. Attached to this large chainring is the small chainring on the inside and a chain guard on the outside.
Someone (not seeing the bike) at the lbs mentioned that the setup resembled that on a BMX bike. Having never studied this before, I wouldn't know. Looking at parts catalogs on the net, there appear to be these single chainrings/chainwheels that are either solid or cutout, but with a single hole in the center for the axle. I've also seen collars/adapters of some sort that fit into those holes for the axle to go through. But both the hole in the chainring and the hole through the adapter seem to be round - what keeps the chainring from rotating on the axles?
Is there any possibility of replacing the chainrings in my current setup? I haven't been able to find any such replacement parts on the net; are they available anywhere? I suppose even if BMX uses a similar setup, there would be lots of other differences prohibiting using their parts - different chain, just a single chainring, etc.
I suppose the expedient solution is just to replace the cranks and chainrings totally with new parts. If that is the case, does anyone sell cheap double chainring cranks that would fit? Would a triple work? I have the old style friction shifters, so there are no detents - it's always been shift and adjust so it sounds right (Shimano Altus front derailleur).
I used to sell Ross bikes and from my somewhat limited memory you have a steel cotterless crankset with, I am almost certain, chainrings that cannot be individually replaced. I think that this bike sold for between $130 and $170 so you got basic bike parts, not replaceable ones. A bike shop should be able to order a set of low price basic Taiwan or Japanese replacement double crankset for perhaps $40 or so. You may have to replace the bb for fit reasons, but that should not be more than $12 to $15. Forget about changing to a triple -it would be very expensive. You would need a new crankset, bb, front and rear derailleurs. Depending on the wear and tear of your freewheel and chain, you may have to replace these too. Old worn freewheels and chains do not work very well with brand new cranks.
I have an Sakae-made crank that I recovered from my sister-in-law's old Motobecane several years ago. It has the Motobecane name cast into the arms but the rear face has "SR" (Sakae's logo) molded in. Anyway, this crank is constructed just like your description and it is Al alloy, including the chainrings.
The outer chainring (52T) is a press-fit onto the crank arm hub and a flange of metal was turned over at the center to, in effect, rivet it in place. It cannot be removed or replaced. The inner ring (40T) is fastened to the outer ring with conventional looking bolts and probably could be replaced except the bolt circle diameter is something like 118 mm (Sheldon Brown says that is an obsolete SR size) and no commonly available replacement rings will fit.
If your crank is made like this one, you have no option but to replace the entire thing.
Kind of off topic but regarding Ross... I recently restored a Ross Beach Commander and have no idea what year it is. I've looked all over the internet for a serial number chart, but haven't found one for Ross. They have them for Schwin, Huffy, Raleigh, but no Ross. Do either of you know of a serial number chart so I can tell what year this bike is. If you need a pic of it, let me know and I can PM it to you.
Hope im not hijacking your thread, but ive started 2 threads w/ this question and no one knows
Thanks jacksbike & HillRider,
I had basically come to the conclusion that even if the pieces did come apart, I wouldn't be able to find replacements for them anyway. So I ordered a new crankset... and some other related parts. I'll know for sure how the old chainrings and crank fit together once I remove them, but it will just for curiosity's sake.
I am quite aware of the chain wear issue! That's where all of this started. I guess I had no idea how badly my chain was worn, but this last time I took it off to clean it I noticed it was in really bad shape. There were six rollers totally gone, one half gone and about to fall off, and one severely fractured. I didn't feel comfortable just replacing links on a chain that far gone, but I knew if I replaced the chain I would have it skipping over teeth. Sure enough, that's exactly what happened with the new chain. Luckily most of the wear was in just two sprockets... the two smallest ones at the rear. The chain skips on those two but none of the others. The bike is still rideable if I stay off those, but obviously since those are the most worn, those are the ones I use most of the time!
The cost of the various parts certainly exceed the price of a new cheap mass market bike, and would be a good chunk toward a decent bike, but this bike is a dear friend after 24 years.
Comparatively speaking, I don't think there were as many Ross bikes made as those other brands, and they weren't around as long either. That probably accounts for the lack of info on them. I know one big factor in why I purchased a Ross bike was because they were made in Allentown, PA, the region that I was originally from.
Originally Posted by MattP.
I've come across at least one reference in a bikeforums archive that says the date is coded with the serial number on the left rear dropout:
On my bike, a 1981 Gran Tour, the serial number there is 0281139087. My guess is that says my bike was made in February 1981. I bought it in May 1981. Although the digits are all adjacent to each other, it definitely looks as if the 0281 was stamped with a different piece of equipment than the 139087 part, as the two portions are not completely aligned with each other.
I also came across this other link in bikeforums on Ross history:
Anybody know the history of Ross bikes?
Hope this helps.
Running a new chain on an old block can accelerate chain wear. Get a new block ASAP. You can even upgrade to a higher number of cogs (eg 5 to 7spd).
I have an SR chainset on one of my old bikes. The chainring is swaged (pressed then squished) onto the crank and they form a single unit.
When I took off the old crankset, I could see how it was put together. Same thing as you described, the chainring is swaged onto the crank.
Originally Posted by MichaelW
I ended up replacing the old aluminum alloy Shimano Tourney double crankset with an ultra cheap steel double one by Pyramid for $17.99. The old aluminum one was feather light, the new steel one weighs a ton. On the other hand, I also replaced the wheels (in the 27 inch size again), both front and rear, including a new freewheel. The new wheels have aluminum rims, the old ones steel rims. So maybe the lighter rims cancels out the heavier crankset and the overall weight is the same.
One thing I noticed immediately about the steel chainrings is they sound different than the aluminum ones. The front shifts have a much more metallic "ding" to them than they used to. A similar thing when applying load again after coasting... that sounds slightly more metallic than before. I guess the softer aluminum tended to dampen these sounds.
The new setup, with new sprockets front and rear exactly replicates the gearing I had before. Same number of teeth on all sprockets.
I ran into one problem that really pissed me off, but it wasn't related to the new parts. I couldn't get the plastic dust cover off one of the cranks. These were threaded in, not pressed in. The slot in the cap deformed and the main part of the cap eventually cracked into pieces. So then I had the threaded part stuck in the crank. I carefully chiseled out that piece being careful not to damage the threads in the crank, as I still needed them to use the crank puller.
Today I got new dust covers at the lbs. I was so enamored by a set of metal caps that threaded in with a hex wrench. On the way home it occurred to me that the hex was probably metric and I don't have a metric hex wrench set. Stupid me. When I got home I thought of a solution... I bet the little hex wrench that is supplied with assemble yourself furniture from IKEA is surely metric since they are a Swedish company. Luckily that little wrench I saved was just the required size!
Anyway, it looks like I am good to go for another 24 years with this bike... by then I'll be dead!