PolarBear007

Hi all -

Not sure if this topic is best posted here to be commented on by experienced touring end-users or in Bike Mechanics Forum to be commented on by the fixers/theorists?

As touring involves long, extended periods of heavy, loaded use over many types terrain and surface sub-strata, I'm wondering about the material used in chain-rings and cassettes/freewheels.

Is aluminum really the best material for touring drivetrains? Does it have as good strength and wear resistance as classic steel componentry? Is there another, better material - titanium maybe?

Realizing that the use of aluminum provides for lighter weight components, better moisture/corrosion resistance (thinking the 7075 alloy) and better availability, I'm still more inclined toward using steel componentry for my upgrade path because I believe steel will ultimately provide longer, better service.

Am I off my nut on this?

Please post your thoughts/comments - I will *definitely* read and consider your advise.

thanks,

frank

thirdgenbird

Most cassettes are steel. Expensive ones do have ti cogs, and aluminum ones exist, but steel accounts for nearly every one.

chainrings are so large that aluminum lasts quite a while. Steel chainrings would last longer, but its hard to find one that is machined for shifting as well as an aluminum ring. Not worth the trade off in my opinion.

pdlamb

Steel holds up a bit better than aluminum, but the quality beats all. Really cheap, house brand cassettes are made of aluminum cheese and wear out very quickly. High end (think XTR) cassettes with fancy alloys are made for racing, not touring. Stick with the equivalent of Shimano LX or XT steel and you'll do fine.

It's unlikely you'll wear out a crank ring in a single cross country tour, unless you maybe do it on dirt and mud. Chainrings are fairly simple to replace when they do wear out, and you can go to steel then.

MassiveD

I just try to avoid the overgearing syndrome. I am not sure that more than 8 speed hub is good for touring, and 7 speed I am fine with. I started with 5 speed but that was limited. This has to do with my needs. A lot of people are fine with the grater cost and lower durability of the 9 speed and on. More gears are good as such, I just don't want to run those chains, or wheels. The stronger chains and wheels you can build in those older systems make sense to me.

You can get the Sugino tripple with steel rings, so that would be an option. The weight of such a set-up would not bother me, but I don't know what if any proof there is of greater durability. I am not worried about Al breaking, the question is whether the overall pattern of chain and gear wear would be improved, and I don't know what would do that. 8 speed and lower chains are cheap enough that you could replace them before they stretch; what about grit lapping; what about the different wear rates of the the different chainrings. Does anyone know what approach would lead to better long term wear?

fietsbob

A variety of aluminum alloys get used for chainrings .. a 7075T6 alloy is used on the premium end of the spectrum .

when I put together my Rohloff bike , I chose a stainless steel chainring . as the wear is all on that one ring



old bike I used steel chainrings too, but the modern shifting schemes have a different set of engineering details

where I am fine with a shifting of gears that is not instantaneous .. friction and just 7 speed , triple crank ..

yes good to think of the actual gear-ratios and not just the number of 'speeds'..

Dfrost 

If the chain is cleaned and lubed regularly, then better steel cassette cogs will last through several chains. I've only replaced a handful of cogs (not entire cassettes) in about 40,000 miles of road use, and replace our chains (higher end SRAM, usually) every 4-6000 miles, and check them often. I've worn out a few middle chain rings (all good quality aluminum) in that time. Granny rings, however, seem far better made out of stainless steel.

bradtx

Frank, IME aluminum (7 series) chain rings last quite a few miles when used for distance riding as for the most part there is only enough torque applied to maintain speed.

I did recently buy a Sugino Impel 150X with three steel chain rings for my beater bike/backup tourer. It shifts fine with an indexed shifter and it's weight is certainly not excessive.

Brad

PolarBear007

Thanks everyone for all the comments/thoughts/ideas. I appreciate learning from you all who have so many more miles in the saddle than me and can speak with experience.

"Aluminum cheese" - that's a new term/concept for me, but I think I understand it... it sounds like a really crappy way to make things - regardless of how low the price point is.

This is what I was thinking - long life and easy replacement (though sourcing is becoming more of a challenge)

I prefer durability and simplicity as long as they accomplish the end goal in a satisfactory manner. I like my 7-speed cog and 3-chainring crank set. Heck, I'd even choose an 8-speed freewheel if it could maintain the durability and give a sweeter ratio!!!

Yeah, I'm too pragmatic to get hung up on how many "speeds" - if equal drive ratios are easily attained I don't much care if it's via a 5-speed or 9-speed freewheel/cassette. So long as long-term durability and ease of service are maintained I'm happy.

That, to me anyway, seems like a great approach. The chain is the "consumable" link in the drive train whereas the chain rings and cogs (ultimately they do wear out) last much longer. Even rims using canti brakes eventually wear out, but longer lasting is for me almost always better.

Thanks Brad, I hadn't seen these Sugino cranks before. I wonder if the rivets could (eventually) be drilled out and replaced with screws...

fietsbob

8th speed was just added on the high end .. 12 screws into a 13, which in turn, screws into the next one

and was a PIA when you had to remove it .. the last 2 cogs had to come off to get a grip on the freewheel removal tool..

to replace a broken spoke who is going to bring 2 chain whips on tour?

bradtx

The Impel crank set is simply inexpensive enough to replace if a chain ring wears out.

Brad

wahoonc

All of my tour bikes are set up with steel granny rings, steel freewheels, yes freewheels 6 or 7 speed. The middle and large rings are usually alloy because that is what was available. One drive train is Deore LX, the other is Suntour XCM.

Aaron

stevepusser

I've seen some expensive aluminum chainrings that were either hard anodized or electroless nickel plated, both of which are very hard coatings, but would like to see some actual testing to see if they improved the life of the teeth under actual use, or just chipped off right away.

Titanium's a very difficult metal to machine, but I see there are some chainrings for sale: Action Tec Its tendency to work-harden may help longevity in those applications...and you pay a big premium for these.

fietsbob

Yea there are the kinds of metal work usually applied only to aircraft or weapons and such , at the cost is no object end. even to bikes ..

side jobs at the aero-space plant areas..



more an old plodding tourist , I got a lot of use of steel chainrings when I was using friction shifting , the tall toothwas OK back then

just shift a trifle past , till it landed over the teeth , recenter the FD cage .. and continue onward.