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Measuring/choosing a fork?

Old 05-20-20, 07:26 AM
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Measuring/choosing a fork?

My favorite bike to ride the neighborhoods around my home has settled into an old Schwinn mountain bike. It's a cheap bike, but the fit is perfect so riding is effortless. And it's the bike I carry on vacations so I don't have to worry about one of my more expensive bikes getting stolen. Early on I rode some off road, but the encroaching infirmities of age and the risks associated with broken bones are such that paved streets or improved hard pack paths will be my riding choices.

The bike as has a decent aluminum frame and okay components, and a suspension fork. The fork is becoming "saggy" and is causing changes in geometry, so I'm mulling the options on repairs or swaps:

1. Rebuild it
2. Replace it with a better suspension fork
3. Replace it with a rigid fork

I'm getting close to retirement. In regards to all things mechanical, minimizing the purchase of "something else that can break and cost money for repairs" has become part of my thinking. Going the rigid fork route is most attractive for the money I will put into this bike.

The choices on ebay literally number in the thousands, so how do I measure / identify the specs on what I have as to assure I obtain a replacement that will bolt right in?

Thanks in advance,

Rick
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Old 05-20-20, 07:38 AM
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My vote is a rigid fork with the same axle to crown seat length as your current fork has WHEN you are sitting on the bike. If possible also match the fork rakes. This will be a close match to the original fork's actual handling. Andy
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Old 05-20-20, 09:33 AM
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How old is the bike?

What fork is on it now?

Since the sagging to bad enough to impact how the bike handles, you may want to approach it from what you have and how it once was, not how it is now.

Get the fork brand, suspension length, 80mm, 100mm, and see if you can find the specs.

Rigid is the best way to go if you are riding on smooth surfaces. You can find rigid forks that are made to replace a particular length suspension fork. You just need to get close. Finding specs of your original will help, but it isn’t rocket science.

If you want to go with a suspension fork, a lot depends on what you have now. If it is an old bike with an elastomer or a newer bike with a spring. A newer cheap spring loaded fork is disposable, an older elastomer may have a parts issue if you want to rebuild.

John

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Old 05-20-20, 09:58 AM
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First decide upon a fork material you would prefer; this will eliminate many choices right off the bat. Aluminum, steel, carbon are the likely choices, I don't see putting a titanium fork on an old Schwinn mountain bike.
Then determine steerer size, this will cut your choices down even more.
My choice would be a rigid steel fork but your choice might differ.
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Old 05-20-20, 11:20 AM
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There are a vast array of Schwinn suspension forks on EBAY, $29.99 and up. You just need to identify the correct one and go for it. Your ride will stay a bit cushier, something to think of in retirement...I just punched in this with an EBAY search, without quotes, "schwinn mountain bike suspension fork". Go for it...
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Old 05-20-20, 06:46 PM
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Originally Posted by bldegle2 View Post
There are a vast array of Schwinn suspension forks on EBAY, $29.99 and up. You just need to identify the correct one and go for it. Your ride will stay a bit cushier, something to think of in retirement...I just punched in this with an EBAY search, without quotes, "schwinn mountain bike suspension fork". Go for it...
Dude, a $30 suspension fork is complete garbage and will definitely just consist of some gaspipe tubes sliding over each other with some springs in there. Fork brand doesn't matter at all.

Anyhow, OP, I'd recommend a steel rigid fork. You'll want to match:
-Wheel size--probably 26.
-Brakes-rim brakes or disc, though you can find forks that do both.
-Steerer-1" and 1 1/8" straight are the likely options for this bike, could be threaded or threadless. If the fork is threaded, you'll need to fairly closely match the length of the steerer. Threadless steerers come really long and need to be cut to length, with a new star nut installed. You can do this accurately enough with a hacksaw or a pipe cutter, and you can install the star nut very carefully by installing a bolt into it and tapping it into the steerer.
-Axle to crown - This is the length of the fork from the wheel axle to the fork crown, which is basically the bottom of your head tube. This doesn't need to be absolutely perfect to the mm, but probably about +/- 10mm is probably a good idea. The ideal is probably about the A2C of the original fork minus about 20% to account for the intended sag of the suspension. You'll also find rigid forks advertised as how much suspension correction they're designed around, which will probably get you close enough to the ballpark.
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Old 05-21-20, 02:34 AM
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The current fork needs to be identified, and also the bike, Schwinn has made high and low-end bikes, if it's old, from the 90's-early 00's it could have been a mid-range bike back then, without knowing what the OP has, anything is guesswork.#

The Schwinn mongrel MTB int he OP's current bikes sounds like a bot of a parts bin special, could be a good LBS version, or a wallyworld version.
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Old 05-21-20, 08:29 AM
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cpach, you are right, my bad. My thinking was skewed, cheap bike, cheap forks. Deleted the post..
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Old 05-21-20, 03:11 PM
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Thanks to all for the feedback. RE, the bike -

It's a wally-world special bought on impulse about 16 years ago. I lucked into a perfect fit, and for years I rode that thing blissfully ignorant of some of the nuances inside the world of bicycling.

"Culture:" not being a bike nerd, it initially took me by surprise when I found out so many bicyclists look down anything but an LBS purchase. And not being much to give a damn what other people think, I read for a while to get my head around the topic, and decided "It fits, and it works, just ride it until it breaks." Later on I shopped discerningly and snagged several great deals on LBS bikes. A couple of high-brow Giant's later, I still like the fit of the low-brow Schwinn the best. As I said in my initial post, "the ride is effortless." Isn't that how it's supposed to be?

At any rate, I don't want to see this discussion go off the rails into a department store vs LBS rant. Since then I've owned both; and I presently own both. Otherwise, I just need to know what fork to put on the Schwinn.

Construction: several years ago I took the Schwinn to one of the local shops for a bit of work, and the tech's response was interesting. His comment: "You know - this thing is really well built and the frame is excellent quality, but the components are junk." So, as things have needed replacement I've just gone with better components. Which again, is my goal in reference to the question about a fork.

So back to my original question, I plan to go with a rigid fork. cpach , thanks for the instruction on how to figure out the fork-match.
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Old 05-21-20, 04:02 PM
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Yeah, I'm an LBS mechanic but I really try not to put out bad vibes on people's inexpensive bikes. It's cool to have "cycling culture" and also not be a jerk to people who just want to ride a modestly priced, functional bike sometimes.The biggest problem with Walmart bikes is assembly. The FS bikes are also just really inadvisable from a fundamental design perspective most of the time also. When Walmart bikes come in the shop I try not to sink too much time in them coming up with a large service plan when the owner (rationally) doesn't want to spend much on the bike, but I'm always happy to relate various recommended services and their costs and let the owner decide. Really cheap suspension forks aren't cheaper and are definitely just worse than rigid forks though, and even on a cheap Walmart bike with mostly poor quality components I wouldn't just throw another cheap fork on. Probably the cheapest forks that are at least decent are the Suntour XCT forks that are basically ubiquitous on $500-$600 LBS bikes, and really those are mostly good for making the bike more comfortable to ride--I still would personally prefer a rigid fork to them.
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