Howdy,

I am interested in anyone's advice about an old mountain bike I just picked up. It's a vintage Diamondback Ascent. I'm going to add fenders and racks - probably a trekking bar. I could stop there to save cash, or make some additional changes. (I figure I can always make more changes later.)

My quandary is over the wheel set. It has a 5 speed freewheel with what looks to be 122 mm spacing and horizontal dropouts. The rear hub seems to be in poor condition. I haven't overhauled the hubs yet. If I find the bearing races are in poor condition, should I move to a cassette, 135 mm spacing and quick release? The bike has non-indexed thumb shifters.

With a five speed cluster it is more likely 120mm spacing. I think it all depends on how good the hub looks and what you plan to use the bike for. I also think you would have to decide if you are willing to put up with friction shifting an older system or if the benefits of an indexed system screams for an upgrade. A six speed cluster with a six speed indexed shifter and derailleur (if you can find them) might be a very nice upgrade, you might not even have to change the axle if it is long enough to work in a 126mm spacing.

Can you get the cluster off without damaging anything?

You really need to decide what you want to use the bike for. My grocery store bike cost $5 at a garage sale, it had been stored outside for over 10 years. But it needed $100 worth of parts and three days of work to rebuild. Now it is a great bike but sometimes you really have to ask how much you really want to put into an old bike. On the other hand the bike on my indoor trainer was saved from a neighbors garbage can and it needed no new parts other than seat and pedals to be a great indoor exercise bike for use on a trainer.

I'd spread the rear to 126 at least... you can run 7 speed cassettes or a freewheel with modern shifting ramps and the friction shifters will work perfectly fine. I somehow broke the indexing on my bar-ends and I shift 9 cogs in friction mode, besides on tour I don't find myself shifting all that much anyway. I'd be more inclined to invest in a 135mm cassette wheel with 8 or 9 gears... I'd guess the DB frame could be spread that far without issue... I'd keep the friction shifters too since I'm a simple dude.

If you're going to carry much on the back you should probably move to some sort of cassette hub since they put less stress on the axle. Around here, decent mtb wheelsets go really cheap, keep your eyes open and you're bound to find something sooner or later.

Personally, I'd stick to 7 speeds or less, especially if you want to go indexed. For touring or just tooling around you don't need that many gears and the tolerances for 7 speed are much more forgiving than 9 or 10 speed. A 7 spd mtb wheelset will often be spaced to 130mm so you won't have to spread the rear end as far either. It is also a lot cheaper to get 7 speed parts than 9 or 10 speed.

If you're on a tight budget I'd just ride it the way it is for a while and upgrade as needed. New cables/housing, chain, brake pads, tires and a thorough cleanup and lube can make a huge difference in ride quality without busting the bank. If you do decide later that you want to upgrade certain aspects then go for up but you might be surprised at how much you like the bike just the way it is before then.

Thanks for all of your advice!

Agreed .

I brought the bike down to a coop today where I was able to borrow the tools and get the help to overhaul the rear wheel. The bearing races and cones looked fine so I think that's the direction I'll take for now. I can always make those changes if the rims aren't holding up. The hubs are pretty nice, but the wheels aren't anything special.

I've already spent more on the bike than I paid for it by buying fenders, touring racks, a new saddle, and some used SPD pedals for it. I found a real interesting handlebar add-on at the coop that's going to give me quite a few hand positions. I think I'm going to really like it once it's all cleaned up!

please post some pics

if it's ~122mm you would be able to fit a 126mm wheel in there pretty easily. Many older 7/8speed 130mm mtb wheels can be converted to 126mm by removing a spacer or two as well.

Pics Added

If I'm enjoying the bike, the only thing left may be the frame eventually .

nice, i believe that's a 1986 model.. in 1987 the Ascent started coming with a hi-ten stays and forks, but that looks to be all cr-mo. I've got a 1986 Apex which was one step above the Ascent in 1986

Cool! Thanks for the info! I was trying to guess it's age and not having much luck. It does have the cr-mo fork.

you can determine the year it was manufactured by looking at the serial #.. the second number should be the year it was made (ie if it's a 6 it's 1986).

Diamondback follows the same serial number format as Centurion (DB and Centurion were both brand names owned by WSI in the 80s/90s) https://en.wikipedia.org/wiki/Centuri...Numbers.5B1.5D

mtnbud, Just ride it when overhauled and cleaned up. Make the fitment right and evaluate what changes can be made. With 122 mm dropout spacing you can easily slip a 126 mm hub into the dropouts for a 7S rear should you wish to.

Brad

Gotta love those vintage, steel mountain bike frames. I found an old Schwinn High Sierra frame that I was able to date by the frame color to 1986. It needed minor work with a torch so the bad original paint job was an asset, not a liability. I spread the rear end to 135 so I could use contemporary mountain bike hubs and 8 or 9 spd clusters. I am tired of fooling around with freewheels. It now has indexed trigger shifters. I love it! If I ever do any serious off road touring I just have to mount racks and I am good to go.

But if you spread the frame out to 135 you can get off the shelf spare parts..
so on the tour failures are easily fixed.

the right set of ratios matters more than speeds , 13- 34 .. 8 will do [48,36.24 crank]