SCbike864

Recently picked up this 1990 Bridgestone MB-2. It obviously has had several components, and drivetrain, switched out. I honestly am not sure what I have exactly.
Are these good changes? bad? eh/whatever? .

After a few rides it seems this 1x is built for faster riding vs. climbing anything. Or am I mistaken in that? These rides were with my kids, but I don't think I once changed to a higher gear. There was no lower gear available to climb (spin faster) on the hills.

Bikes in great shape though, well maintained, and recently tuned prior to picking up. Just not exactly sure what I've got as far as components/drivetrain vs. what originally came on it.

Thanks!

AeroGut

The original was Suntour XC per catalog: https://www.sheldonbrown.com/bridges...ne-1990-06.htm

AeroGut

The 105 group on there is late 90s road, which only matters in that the 130 bcd means you can only go as small as 38t on the chainring unless it's the triple version in which case you can put something smaller on the inside position but the chain line will be weird.

SCbike864

So if I'm looking for more of just cruising and/or all around speed and gearing I'd be better off trying to find the original Suntour on eBay (used)?
I wonder why the original owner switched to the 105? Other than top end speed, it seems to take away versatility.

bboy314

MTB with a road drivetrain - definitely not built for climbing. Nice brakes and other components though. I’d change out the drivetrain for lower gearing (new crankset at the least, possibly different derailleur and cassette too) if it were mine.

AeroGut

no need to go back to the original SunTour stuff. I would start with just swapping the crank/BB for any decent MTB triple (or double depending on what gear range you want) that fits (ie threaded BB pre boost spacing) and add a front derailleur. If you get a crank designed for the number of gears you have in the rear already (looks like nine), then the chainrings will be compatible with the chain you've already got.

Frkl

You've got a highly desirable frame (Petersen designed, lugged Ritchey Prestige, fork also, near top of the line) in really great condition, but which has had basically every component switched out. Some of the choices were . . . not what I would have made . . . but all are good components: 105, LX. It has been set up as a flat town bike, or a canal path bike, i'd say.

The minimal change to get better climbing would be to add a granny gear to your triple 105. I think its a 74 bcd. You would need a front shifter and a front derailleur too. If that isn't enough, shimano is really conservative on the range specs for its derailleurs. You could probably get it to work with a 32, maybe even a 34 cassette.

I would resist getting a huge range cassette and new rear derailleur (so modern 1x set up) they just don't look right (in general and especially on that frame, in my opinion, of course.)

RB1-luvr

it's a beaut!

joesch

Just swap on a bigger chain ring.
Going 1x without making the rear changes just limits the speed or climbing.
Can go back to 2x or 3x but will of course need a FD and its shifting controller

SCbike864

Any recommendations on a compatible 2x?

SCbike864

any suggestions off the top of your head on a replacement 3x, or 2x?

Im gonna try to do some digging this weekend when I have more time.

AeroGut

If you want to be matchy-matchy, the LX M570 triple crank that goes with your brakes was a nine-speed. If you want to go with Hollowtech II instead of square taper cranks, the Deore 590/610 triple crank is a newer 9spd that works great.

LesterOfPuppets

If probably get a triple shifter FD/shifter in case you want to go triple, as that looks like a triple crank set. You can go double on it just by using the FD limit screws.

Tiagra or Claris road triple flat bar shifters and front derailleur are options.

VtwinVince

Very nice frame and fork, the rest is meh.

bikingshearer 

It looks like just about every component was swapped out. That is a 1990 model, according to AeroGut's catalog link (than you). The catalog shows, among other things, that it originally came with cantilever brakes (no surprise on a Grant Petersen-spec'd bike from that era). 9-speed drivetrains did not exist in 1990, so that is a previous owner's modification, and it likely means that the rear tringle was spread - not a problem. So what have you got? A good frame and fork that has a drivetrain that does not work for you.

I'd say get a used triple crankset with a 110/74mm bolt center diameter set-up. That will allow you as a small chainring as 24 teeth, which should give a low enough gear to get up anything you are likely to encounter. Pretty much any 1980s or 1990s era Shimano mountain bike crank will have that, as will old Avocets and Specializeds and new stuff from Velo Orange or Rivendell. As mentioned, you will need a front derailleur (triple specific - old Shimano is probably the easiest to find) and a way to shift it (someone else will have to advise you on this). You may also need a new bottom bracket with a different length axle. I'd say try the new crack on the current BB to see if it will work. If not, someone here should be able to help guide you through the thicket of what length to get.

LesterOfPuppets

It was probably already a 135mm OLD. I know my '91 is anyway.
It already has a 110/74 triple crankset, it's just missing big and little rings. It is a road triple however, which requires a road triple shifter, or friction shifter, or 10-position Gripshift, or...

79pmooney

@scbikes864, does your current crankset have bolt holes for a smaller inside chainring? I cannot tell from your photos. Need to look at the inside of the crank spider. If yes, turning it into a good triple will be easy. That inside bolt pattern is probably 74 BCD. Very common. And you can take off the outside guard and put on whatever outside ring you want or move your current ring to the outside and buy a ring sized between your current and your new little inner ring. If the bike now has a proper chain line with the sole ring on the inside, you have all you need for a properly aligned triple - as long as you keep that crankset. Change it and not the bottom bracket also and you've just opened a can of alignment worms.

Look at that crankset for the inner ring bolt holes. If yes, sweet gearing will be easy and cheap. Two chainrings and some bolts. (You will probably need the right crank removal and installation tools also to get that inner ring on. Juggling it past the spider might be possible but I won't promise. Good tools to have on hand anyway if this is to be your bike.)

LesterOfPuppets

You can see the bosses for the inner ring. Kinda looks like they left the chainring bolts in there too, which is nice.

SCbike864

LesterOfPuppets and 79pmooney and others, sorry for the delayed response.

yes it looks like it does have the ability for smaller chain rings and the old bolts were left.

if I’m looking for more range, would it be possible/better to find two smaller chain things and just put them on this, making it the triple the 105 was originally?

it being road components okay? Or is it something I’m just wasting time/energy/money on and need to just remove it all and start anew (old stock)?