Harhir

I just got me a late 90s Mongoose mountain bike which is still in pretty good shape. Nothing fancy, old style steel frame. Just needs a little TLC like brake adjustment, shifter adjustment, cleaning and surface rust treatment on some bolts. It was almost for free and I could not resist since I was looking for a large frame bike and this is a 24" frame.

I am planning to use it as an occasional mountain bike on very moderate trails and as a backup commuter bike. However since this bike has a rigid fork I wonder if that fork could be swapped for a suspension fork. Not sure if it is worth it but I just wanted to check.
Are there any aftermarket suspension forks for these old bikes?

Thx
Stefan

dabac

What size steerer tube is it?
What kind of headset is it?
1 1/8" steerer tube forks are still readily available.
If your current headset is threaded, you might find it simpler to go to an aheadset/threadless setup while you're at it.
You're unlikely to be able to find a used fork with a long enough steerer for that frame size.
Your (main) concern will be length of travel. Frames designed as rigids tend not to be entirely happy when built up with sus forks due to how much it jacks the front end up and changes the fork angle. Steering tends to become slacker/slower.
There's a bit of added risk as the slacker fork angle puts more stresses on both fork and frame.
You might even want to look for one of those short-travel(abt 60 mm) forks for hybrids.

grubetown

Unless you install yourself, it is going to be a little bit of an expense to switch to suspension, probably $200-500. There are still 26" suspension forks available. If it were me I would leave it rigid and save/spend the money on some other bike related items like V brakes if it doesn't have them.

Harhir

Thanks for the explanations. I have no idea if the headset is threaded or not. I need to measure the tubes to find out what size they are. But it does have a very long steering tube. The picture below is not my bike but it is the same frame size.
As for the brakes: These are cantilever brakes. I need to adjust them and put some new shoes on. After that I decide if V-brakes are really necessary.

gsa103

Wow! You must be tall! That is a giant frame. That's a standard threaded headset with quill stem. I'm not sure anyone ever made threaded suspension forks since they transitioned to threadless about the same time.

There's a good chance that it would be more cost effective to buy a different bike. Given the frame size, I would highly recommend a 29er.

Harhir

Yes this is a 24" frame. It just looks that big because it only has 26" wheels. I currently ride a European Style touring/trekking bike with a 60cm (approx 24") frame with 700c wheels.
I have been looking for a while on sites like Craigslist for newer mountain bikes with 29" wheels and a similar frame size but they hardly ever show up that tall. Or they are ridiculously expensive. Too expensive for what I am going to use it for.
I only paid $40 for the bike. Tires are still good, gears show little wear and it only needs some minor TLC. The previous owner only rode it occasionally on paved neighborhood trails. Never offroad.

I am going to try this for a while. If it does not work I haven't really lost anything and I can still keep it as a backup bike. One can never have enough bikes.... lol

Trevtassie

Far out, that's a tall frame!... Biggest problem I can see is what Dabac says, but even more so given the tallness of the frame, sus forks will throw your weight right back by lifting the front, the seat is already a good ways to being over the back axle as it is. With a front lift it'd move the seat back even more, it'd be good for wheelies but not much else. Hell, you may even struggle to find a threadless steerer that long. If the levers and everything are in good order, I wouldn't worry about swapping out the canti's unless the levers are convertible to V brake. Just whack on a new set of pads because the old ones are likely like concrete and will tear up your rims.

ToddSantora

Wow! If you have a few beers you better bust on the training wheels for that Mongoose! You could hurt yourself falling off of that thing!! That is one BIG frame!
I had a Mongoose when I was a kid and I loved it! My favorite bike by far! You need one of those truck steps mounted on that thing!!!

elmore leonard

That is a good question.
I too would like to get the same advice on a good web site that sells after market front suspensions for 90's mountain bikes. Even a good web site that sells them for later bikes with front suspensions.

jimc101

Any current suspension fork that is the correct spec (i.e. 1 /8" straight steerer) will fit a late 90's MTB, just choose the appropriate travel (for an late 90's bike this will be around 100mm. if it's pre 1994/5 then there are other issues, you need to be more specific on when in the 90's your bike is from.

For that Mongoose, the steerer will probably be the biggest issue, guessing it's 1' add to that it's threaded & the length would leave it rigid as it would be easier to buy a new bike than source a part that has been obsolete for 20 years (if it ever was made)

unterhausen

as has been stated above, you probably don't want to put a suspension fork on a frame that isn't suspension-corrected. You can tell a suspension corrected frame because there is a lot of clearance above the tire. I have the opposite problem, my commuter is suspension corrected and doesn't have a suspension corrected fork. Handling is horrible

Azreal911

Funny thing is I own a 97 wheeler and really like it and have no interest in a new bike but my old shocks wore out to the point of bottoming out and not coming back up I've basically took it out and put in a rigid fork with a aheadset/threadless setup. But instead put on some 2.35 wide fatties (schwalbe fat franks) for smoothing out singletrack riding. The bike is alot of fun now on road (50psi) and off road (25psi).

it's alot of fun for me to keep my old frame and my next diy for the winter would be a new alivio 3x9 groupset on there for not much since my front crank is starting to shark teeth and thin out (no 5 bolt replacement chainrings these days!), I commute with the bike too every so often so i don't want to get too crazy and lock up some expensive parts on there even though our bike rack is underground and right next to the parking managements office with a window.

oh I have canti's also and when i changed out the fork the LBS did the conversion for me and they tuned up my front brakes correctly, you can stop on a dime with it! I could never set up my canti's as amazing as how the store did it though. But yeah if properly setup i don't think you need v-brakes at all.