Go Back  Bike Forums > Bike Forums > Commuting
Reload this Page >

Rigid MTB Fork: Why is this so HARD??

Notices
Commuting Bicycle commuting is easier than you think, before you know it, you'll be hooked. Learn the tips, hints, equipment, safety requirements for safely riding your bike to work.

Rigid MTB Fork: Why is this so HARD??

Old 10-06-12, 07:49 AM
  #1  
steve-in-kville 
Warehouse Monkey
Thread Starter
 
steve-in-kville's Avatar
 
Join Date: Jul 2008
Location: Lebanon Co., Pennsylvania
Posts: 1,600
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 302 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Rigid MTB Fork: Why is this so HARD??

So I am exploring replacing my 80mm stock Suntour fork for a rigid on my HardRock. I am poking around on ebay as well as other websites. I measure my axle to crown and I am about 457-ish mm.

I have heard the term "suspension adjusted" before? What does this mean exactly? Do I go to a shorter rigid fork? Stay as close to the same? The forks I am looking at on ebay seem to be a lot shorter, like 410mm or so. I feel like I am missing some vital info here.

Also, a 1-1/8 steer tube is the same as the next? I don't need to change anything bearing-wise in my steer tube, correct? I should be able to slip my stock fork out and the new one in?

Let me know if this thread needs to be taken over to the Mechanical forum. I realize this is getting more involved for the commuting forum.
__________________
'10 Specialized Hardrock
steve-in-kville is offline  
Old 10-06-12, 08:17 AM
  #2  
chaadster
Thread Killer
 
Join Date: Aug 2008
Location: Ann Arbor, MI
Posts: 10,410

Bikes: '15 Kinesis Racelight 4S, '76 Motebecane Gran Jubilée, '17 Dedacciai Gladiatore2, '12 Breezer Venturi, '09 Dahon Mariner, '12 Mercier Nano, '95 DeKerf Team SL, '19 Tern Rally, ‘21 Breezer Doppler Cafe+, ‘19 T Lab X3

Mentioned: 21 Post(s)
Tagged: 0 Thread(s)
Quoted: 1520 Post(s)
Liked 575 Times in 351 Posts
It shouldn't be too difficult to find a replacement rigid fork, since most of the rigid forks commonly available are designed just for this application (i.e. replacing suspension forks). In particular, they're taller than older rigid forks that were designed in the early bike suspension era. Today's frames, largely, are designed around suspension forks, so the geometry takes the added height of a suspension (aka springer) fork, and sag, into account.

It used to be, back in the days (!), that when you stuck a springer on, it would jack up the height of your front end and change the handling characteristics of your bike. "Suspension adjusted" frames tackled that problem head on, and today, the tables are turned such that if you want to ditch your springer, which is the industry standard fork, then you need to get a "suspension adjusted" rigid fork!

More to the point, you need to make sure that you have enough steerer tube length to accommodate your frame/headset stack height. Diameter should be fine, and you should be able to easily swap the lower bearing race from the old fork to the new one. There may be some newer format I'm not really hip to, like integrated headsets, which may throw another factor into the set, but I don't think that's an issue with your HardRock.

Assuming you like your riding position and handling with the springer on, armed with headset type, steerer diameter, steerer length, and fork length, you should be able to move forward with selecting a rigid fork. The only other thing I might add is that you may want to look at fork features, e.g. braze-ons and brake mounts, and rake, the offset of the dropouts from the centerline of the fork legs. I don't know the geometry of your frame, but I'm guessing that anything in the 45mm-53mm range would do the trick, but again, matching that number to your existing fork is best if you want to keep the same handling characteristics.

Hope that helps, and good luck!
chaadster is offline  
Old 10-06-12, 08:51 AM
  #3  
steve-in-kville 
Warehouse Monkey
Thread Starter
 
steve-in-kville's Avatar
 
Join Date: Jul 2008
Location: Lebanon Co., Pennsylvania
Posts: 1,600
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 302 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Yes, this was helpful. Thanks for the reply.
__________________
'10 Specialized Hardrock
steve-in-kville is offline  
Old 10-06-12, 09:45 AM
  #4  
jeffpoulin 
Senior Member
 
Join Date: Jul 2008
Posts: 2,296
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 49 Post(s)
Liked 11 Times in 7 Posts
Regarding the fork installation, there's more to just taking the old one off and putting the new one on. In particular, you'll need to transfer the headset crown race. This is not always easy as it's a very tight fit.
jeffpoulin is offline  
Old 10-06-12, 10:11 AM
  #5  
fietsbob
Banned
 
Join Date: Jun 2010
Location: NW,Oregon Coast
Posts: 43,599

Bikes: 8

Mentioned: 197 Post(s)
Tagged: 0 Thread(s)
Quoted: 7607 Post(s)
Liked 1,318 Times in 828 Posts
I have heard the term "suspension adjusted" before? What does this mean exactly? Do I go to a shorter rigid fork? Stay as close to the same?
Shorter fork blades has the head tube angle steepen, as the frame rotates down to meet the shorter fork.

When you get on a suspension fork bike, your weight compresses the suspension some,
so the fork crown race to axle center line can be a little less ..

May me easier to knock out the headset bearing parts, with a big screwdriver ,
out of the frame,
than pry the crown race off the old fork, so consider another headset as well, ..
fietsbob is offline  
Old 10-06-12, 11:10 AM
  #6  
mbryant52
Senior Member
 
Join Date: Mar 2011
Location: Bellingham, WA
Posts: 62

Bikes: Surly Big Dummy, Waltworks singlespeed 29er

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Surly 1x1 fork. Problem solved.
mbryant52 is offline  
Old 10-06-12, 01:14 PM
  #7  
steve-in-kville 
Warehouse Monkey
Thread Starter
 
steve-in-kville's Avatar
 
Join Date: Jul 2008
Location: Lebanon Co., Pennsylvania
Posts: 1,600
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 302 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Thanks for the replies. If the mods think this thread needs moved to the Mechanical forums, please do so. I didn't intend for it to get technical like this.
__________________
'10 Specialized Hardrock
steve-in-kville is offline  
Old 10-07-12, 07:13 PM
  #8  
nfmisso
Nigel
 
nfmisso's Avatar
 
Join Date: Mar 2011
Location: San Jose, CA
Posts: 2,991

Bikes: 1980s and 1990s steel: CyclePro, Nishiki, Schwinn, SR, Trek........

Mentioned: 12 Post(s)
Tagged: 0 Thread(s)
Quoted: 383 Post(s)
Likes: 0
Liked 4 Times in 4 Posts
As alluded to above - you need to measure your current fork with you on the bike to get the actual axle to crown distance that you need for a non-suspension fork.
nfmisso is offline  
Old 10-07-12, 10:08 PM
  #9  
unterhausen
Randomhead
 
Join Date: Aug 2008
Location: Happy Valley, Pennsylvania
Posts: 21,601
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Liked 1,324 Times in 960 Posts
typically, a suspension corrected fork is shorter by 25% of the travel. This is often called the "sagged" length of the fork. In your case, it would be 20mm off of your A/C measurement..
unterhausen is offline  
Old 10-07-12, 11:03 PM
  #10  
turbo1889
Transportation Cyclist
 
turbo1889's Avatar
 
Join Date: Aug 2011
Location: Montana U.S.A.
Posts: 1,206

Bikes: Too many to list, some I built myself including the frame. I "do" ~ Human-Only-Pedal-Powered-Cycles, Human-Electric-Hybrid-Cycles, Human-IC-Hybrid-Cycles, and one Human-IC-Electric-3way-Hybrid-Cycle

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 22 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
I put a $60 on sale 29er rigid fork on as a replacement for my 26" wheel suspension fork and kept the 26" front wheel. Worked like a charm and the extra length of the fork for the larger size wheel matched the length of the old worn out suspension fork nearly perfectly but I had disk brakes wouldn't work with rim brakes. You didn't say what size your front wheel was but if it is a 26" wheel with a short travel mountain bike type fork on the front and your running disk brakes then check the selection of 29er rigid forks and you might come up lucky like I did.
turbo1889 is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
SeraphimF
General Cycling Discussion
14
05-09-18 06:59 PM
AST236
Bicycle Mechanics
6
07-02-14 01:27 PM
Telly
Bicycle Mechanics
16
11-14-13 08:58 PM
Telly
Bicycle Mechanics
10
12-18-11 11:03 AM
bamster
Bicycle Mechanics
4
08-09-10 04:22 PM

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information -

Copyright © 2021 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.