Vintage MTB conversion

[zennmotion]

I have a 1995-ish Bontrager Privateer hard tail that's been in mothballs for a long time. It's time to get either get rid of it or try to do some minimal updating and putting it back in service- as a project (it has no market value) and I have no other MTB and it would be fun to do some off-road on something besides one of my rim-brake CX bikes (which have been fine for pretty much everything I've done, but have obvious limitations). "Features" in the Bonty include a 1" head tube and canti brakes. I did upgrade the original Rock Shox elastomer fork to a Marzocchi Z3 (oil) that has seen minimal use, so it should still be in good shape, and has both canti studs and a disc tab. I think (?) it has 100mm of travel IIRC. What I want to do, if I can, is update this thing if it makes sense to 27.5 wheels and disc brakes. It still won't be a modern hardtail but I figure it might be a decent bang for the buck to have a somewhat updated trail bike. Another new or new-to-me MTB is out of the question at this time- it's either ride the Bonty as is (still needs some work), update it or give it away to the local coop. Oh and I'm moving so some stuff has to go, but I loved the Bonty BITD. So tell me why I can't do this-

Build new disc wheels with 27.5 rims- how do I measure to see if the front wheel won't bottom out against the fork crown (100mm travel IIRC- or maybe 120, I dunno)- I think I'm fine with the larger rear wheel. Suggestions for decent but inexpensive 27.5 rims? Or maybe I just build or find a set of used 26 in disc wheels?

Bolt-on disc mount for the rear wheel- I've seen several models, the 4130 stays should be robust enough to resist flex, right? Anybody with experience with these? Can the pads be accurately aligned with the rotors? What size rotors would be best- I assume the larger the rotor, the more accurate the alignment needs to be due to the increased radius increases the chance of misalignment, right? I know the bolt on looks like crap. No problemo in this case!

I have no (none, nada, nyetski) experience with disc wheels/brakes. Assuming I have good hub skewers and keep them tight, quick release wheels are safe enough, right? The fork still has the lawyer tabs and who cares about the rear dropouts-

What size rotors and what cheap but pretty good brakes? Mechanical or basic hydro to keep the bang for the buck in the non-stupid range?

Bonus question- cheap dropper 27.2mm seat post? I rented a real 29er and did some horrific (for me) trails in Thailand and really liked the dropper, but maybe it's too stupid expensive for a shade tree hack project.
Thanks for any ideas!

[Ken Robb]

Just tune it, put on some nice fat tires/tubes and enjoy it as is. I don't think spending $$$ on new wheels and disc brakes will increase your enjoyment enough to justify the expense. Even if you can use slightly bigger 27.5 wheels they may prevent you from using tires as fat as you can with your 26" wheels.

Once you put some miles on this bike you should have a good idea of what mods you MIGHT want to make to it but I'll bet you'd do better to buy a different bike to achieve your goals.

[zennmotion]

Originally Posted by Ken Robb

Just tune it, put on some nice fat tires/tubes and enjoy it as is. I don't think spending $$$ on new wheels and disc brakes will increase your enjoyment enough to justify the expense. Even if you can use slightly bigger 27.5 wheels they may prevent you from using tires as fat as you can with your 26" wheels.

Once you put some miles on this bike you should have a good idea of what mods you MIGHT want to make to it but I'll bet you'd do better to buy a different bike to achieve your goals.

OK, I hear that voice in my head too- what about the idea of a "mullet" bike- just add a new 26in front wheel/ front disc brake? The bigger conversion idea is partly driven by the need to tinker, projects are kind of therapeutic, building is more fun than buying. But there's sense and nonsense And oh yeah- new wheels mean tubeless, so another major post 90s advantage!

[foo_fighter]

At least put some V-brakes on there. Those are cheap. For tires, just get the biggest 26" front tire that will fit. You can try to "ghetto" tubeless the wheels.

[ofcounsel]

Originally Posted by Ken Robb

Just tune it, put on some nice fat tires/tubes and enjoy it as is. I don't think spending $$$ on new wheels and disc brakes will increase your enjoyment enough to justify the expense. Even if you can use slightly bigger 27.5 wheels they may prevent you from using tires as fat as you can with your 26" wheels.

Once you put some miles on this bike you should have a good idea of what mods you MIGHT want to make to it but I'll bet you'd do better to buy a different bike to achieve your goals.

This. Throwing new wheels/brakes at this bike makes no sense: Neither financial nor function wise. Just ride it.

If, after riding it as is for a while, you decide you're really into the notion of tooting around on a mountain bike, then give your current mtb away to bikeless person, and get yourself something proper.

[taz-t]

If you do try these mods, let us know how it works out.

I have a Bonty race lite and an steel Ibis mojo that I can't bring myself to get rid of but they're not getting ridden currently.

I've played with the idea of a new mtb but can't justify it at the moment.

- taz

[oliver1850]

Originally Posted by zennmotion

OK, I hear that voice in my head too- what about the idea of a "mullet" bike- just add a new 26in front wheel/ front disc brake? The bigger conversion idea is partly driven by the need to tinker, projects are kind of therapeutic, building is more fun than buying. But there's sense and nonsense And oh yeah- new wheels mean tubeless, so another major post 90s advantage!

Sounds reasonable to me. Shouldn't cost a whole lot to put a disc on front. If I was going to try 27.5" I'd want to borrow wheels/tires and check fit first.

What color is the Privateer? I have one that I thought was a '95, it's dark green and has a rigid fork.

[zennmotion]

Originally Posted by oliver1850

Sounds reasonable to me. Shouldn't cost a whole lot to put a disc on front. If I was going to try 27.5" I'd want to borrow wheels/tires and check fit first.

What color is the Privateer? I have one that I thought was a '95, it's dark green and has a rigid fork.

It's black with gray graphics, I think it was the Comp model- 2nd tier with XT components and a yellow Rockshox elastomer fork. The Marzocchi oil bath fork was a good upgrade, heavy but good damping without rebound- a major technology advancement at the time. I need to figure out how to replace the oil and adjust it properly, it's been a long time since I worked on anything with suspension. If I ever repaint it (unlikely given the age and the scars were well earned) the green would be the way to go. I believe that the frame is an early Trek factory version of the handbuilt racelight, same geometry, probably heavier tubing and of course never saw Keith's jig.

[oliver1850]

I think both of us have 1996 frames. Privateer came with either rigid or Rockshox Quadra 21R forks.

http://www.retrobike.co.uk/gallery2/...trager1996.pdf

[zennmotion]

Originally Posted by oliver1850

I think both of us have 1996 frames. Privateer came with either rigid or Rockshox Quadra 21R forks.

http://www.retrobike.co.uk/gallery2/...trager1996.pdf

Looks right, except my logo graphics are gray and not red as spec'd in your link. Back then the components didn't change so quickly each model year, although the tech revolution for MTBs was on the near horizon! I remember it was all good (we had no idea what was coming) except the original 21R suspension fork was pretty bad (your rigid was the way to go), and the saddle was like sitting on a 2X4. Funny because it was basically a Concor Lite with the corners cut off, and I loved my Concor Lite. If I remember, the buzz about these was about the geometry, very short and tight compared to what else was out there at the time- it climbed very well on steep and loose terrain. I dunno- I'm tempted to troll the classifieds and ebay and see if I run across some cheap used parts, since even the upgrades I'm asking about are also themselves getting pretty dated. But I think the main thing is just to get it fixed up and ready to ride first, too busy with the move to consider a bike project for a few months, but something fun to think about. I hate the idea of not having a MTB even if I don't get on technical trails very often- bay area move may change things and I will be humiliated by teenage boys (and girls) no matter what I'm riding offroad. BTW, I think I sold you an old Czech steel road F/F- the red Sirer that speed wobbled on me a couple times. Good to see you're still alive!

[oliver1850]

I've had mine for a few years but have yet to build it. Considered it for my Campagnolo group but it's really too new for that. Will likely end up XC Comp unless I stumble on a nice LX or XT group.

Agree that tech changed rapidly in that era. I was amazed how much faster I felt on my first ride on a 2002ish Serotta soft tail compared to the mid 90s MTBs I was used to.

I did a very simple Exage 7 speed build on the Sirer. Been a while since I rode it but never had any speed wobble issues with it. It's a nice frame. I bought it thinking I would get my Czech friend interested in road bikes and give it to him, but a 30 mile ride in 90 degree temps and 75 degree dew point soured him on the idea.

[edukaycheon]

It probably won't ride the same as any other MTBs you might be used to, so I'd go period correct with whichever "upgrades" you might want and embrace it as it is without throwing too much money at it

[d_douglas]

Yes, no discs. This bike is too vintage to mess with new tech like discs and droppers. Just put v’s and fat rubber and a 700mm bar on there and it’ll be a blast!

Or if it’s an XL, ship it to me - I love those vintage MTBs!

[Red Tornado]

Originally Posted by d_douglas

Yes, no discs. This bike is too vintage to mess with new tech like discs and droppers. Just put v’s and fat rubber and a 700mm bar on there and it’ll be a blast!

Or if it’s an XL, ship it to me - I love those vintage MTBs!

My suggestion is to ride it with the period-correct parts, where applicable, and enjoy it for what is is - a trip down memory (or nostalgia) lane. I still have a '95 Giant ATX Al 1.75 frame built with Judy XC, Shimano LX and other mid-late 90's stuff. Even run canti brakes. Occasionally it's a nice change to ride something a little different, makes me appreciate some of the higher-tech stuff we have today and reminds me of a time when I actually was fast.
Your decision, just a recommendation from me.

[RFC]

Keep it as is and enjoy it.

Here is mine -- a mid 90's Litespeed I have turned into my suburban trail bomber and ride to the gym bike. Mid 90's MTB geometry and fit are iconoclastic.

IMG_0361 by Robert Copple, on Flickr