Swap a mountain bike shock fork for a rigid touring fork??

I want to lose the weight of the mountain bike fork. I would like to do some longer distance touring this season and want to put a chrom/moly touring fork on my bike with eyelets and braze-on for mounting a front rack and fenders. I have a threaded 1 1/8" with a quill adjustable headset and riser handlebars. My bike is a Schwinn with the factory Suntour SR fork. I have a light bar mounted to the fork for my lights and camera. I use a SON generator and a solar panel to power my lights and my phone which I use as my bike computer.

I already have a rear rack on it and clearance for my heels for my panniers. I've riden 1100 miles since November 1. The bike fits me very well so until such time that I can afford a lighter frame genuine touring bike I'd like to use this one.

 

I would appreciate any suggestions or help.

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Permalink Reply by Joe Torres on February 14, 2012 at 8:31pm

Hello Lee,

Looking at the picture provided it appears that your bike may be on the older side. In order to install a rigid fork for your bike you will need to keep in mind of a few things in addition to the fork. You will need to find out the suspension travel of your fork to get a fork that is suspension corrected to that length of travel. This keeps the geometry the same.

Look at Surly or Salsa for a suspension corrected fork with your wheel size and brake attachment. The Surly Troll fork is suspension corrected for 100mm of travel and the Surly Big Dummy fork has 80mm of suspension corrected travel, attachment for a front rack too. You may be able to use the current V-brake set-up too.

Also you will need to swap out the older style headset and install a newer stem, because a later model fork will not have a threaded style set-up. (Cane Creek 40 is excellent, affordable and reliable)

Keep in mind also that if you find a fork that is only disc brake compatible you may need to upgrade your hub to accept a disc, buy a disc brake set-up and longer cable.

Hope this helps.

Joe T

2Bici Bike Shop

Permalink Reply by Kevin Mulcky on February 15, 2012 at 4:35am

Joe is spot on here, it's going to be hard to find a touring fork in 1 1/8 threaded, but it looks like the Big Dummy fork might be your best bet since it has more braze-ons for rack mounting and/or accessory mounting. Your might want to double check the axle to crown measurement on your current fork against your new fork to make sure there's not a significant change in length, because that will change the headtube angle and the handling of the bike.

Permalink Reply by Lee Rogowski on February 15, 2012 at 4:40am

Thanks for your reply!

I've found forks on these web sites and your response answered a big question I had about the 100mm or 80mm numbers I was seeing. How do I measure this?

 

I've found these two sites carrying threaded suspenson corrected 1 1/8" rigid forks.

http://www.bikester.co.uk/bicycle-parts/rigid-forks.html

http://www.sjscycles.co.uk/thorn-mt-tura-1-1-8-inch-ahead-80-100-mm...

Once I know how to measure suspesion correction and once I know whether I need a 80 or a 100, do you think I'd be able to use either of these and use my current stem?

Permalink Reply by Kevin Mulcky on February 15, 2012 at 4:57am

you can try ebay for more 1 1/8 threaded forks, but if you're keeping your headset, you'll need to find a threaded fork with approximately the same steerer tube length. That Thorn fork steerer is waaay to long.

http://www.ebay.com/sch/i.html?_from=R40&_trksid=p5197.m570.l13...

Permalink Reply by Far'arned Retrogrumpalunkus #63 on February 15, 2012 at 5:24am

Another low-cost down and dirty option would be to find a used non-suspension cross or MTB fork from the 90's at working bikes that was from a BIG-framed bike with a longer 1-1/8 steer-tube and suspension-correct by putting threadless shims at the bottom of the steerer.

As long as you have enough threads on the steerer tube you can cut any extra off (or shim the top too between the top race nut and the locking nut.   It might be ugly but no uglier than a suspension fork which is already pretty ugly.  Even a heavy non-suspension fork should save you weight over what you have there. 

Yet another option is to find a low-cost suspension-less frameset at WB or off of CL and just swap your components.  This would probably be cheaper and quicker than messing around with a buying a fork at retail and you'd get rid of the Schwinn frame in the process.  In the end it is still a Schwinn even if you replace the front fork. 

Permalink Reply by Joe Torres on February 15, 2012 at 7:00am
Lee,

Do a search on your current fork and it should tell you the suspension travel. If the travel is 80mm then you will need a suspension corrected fork of 80mm.

http://www.treefortbikes.com/#navbar=pro___333222350524___82

The forks you found are out of the UK and that may be an issue if they need to be serviced in the future.

If you have the original fork on your bike then I'm guessing it has a lot of age on it. The issue with older suspension forks is parts are scarce, the oil in them break down the internals over time and you may be working even harder to pedal your bike because of the unwanted bobbing of the fork. If you did 1100 miles on your bike that is very impressive because riding with an old fork like that is not easy.

If you are happy with your bike and willing to spend at least $200 (not including labor) on this upgrading I say do it. Or spend a few hundred dollars on a new bike with all the upgrades and be done with it. Nowadays you can get a KHS or Cannondale well equipped for commuting for $500 or $600.

Eitherway, any feedback you need I will be happy to assist.

Joe T
Permalink Reply by Lee Rogowski on February 15, 2012 at 7:19am

I'll look on Working Bikes, Thanks for the suggestion! I've been looking on CL.

I am going to the swap meet on Mar 3 to look for a different frame to build up. Is a 26" or a 700c better for touring? Because I have the investment in the SON dynamo hub laced into a 36 spoke 26" wheel suitable for touring, I'm leaning toward staying with a 26" frame and 26x1.4 tires. I've switched out to an 8 speed touring cassette with a new Schimano Altus derailer and have a Suntour triple chainring with a granny gear. These gears fit me very well on this bike.

In the meantime, I still have a Schwinn that fits me and that I've riden well over 3000 miles already. I've spilled it twice fully loaded and I've gotten hurt way worse than the bike! Its a tank.

On eBay there is a 25 cm threaded fork with 10 cm threaded. I can't tell what the suspension correction is or the length of the fork.

http://www.ebay.com/itm/BLACK-STEEL-1-1-8-26-MTB-BIKE-THREADED-FORK...

 

On my Schwinn Mira-Mar, I measure 42cm from axel to crown and 16cm for the steerer tube for the SR Suntour M2025 suspension fork.

These are the specs off the Suntour site (http://www.srsuntour-cycling.com/index.php?screen=sh.detail&int...) for my M2025 suspension fork. I'm not experienced enough to know how to read these and compare them to what is available for sale or even to what I've measured! I'd appreciate anyone who can interpret these for me!

Travel
63 (50) (30)
System
Coil spring
Lower
Steel
Design
Leading axle
Dustseal
Resin
Leg Color
Gloss black, Metallic silver, White
Crown
Alloy
Pitch
126mm
Integrated HD
Semi ID type / 43mm
Stanchion tube
STKM
Stanchion tube finish
CP finish / Miniboots
Finish
Black or Barrel
Right Side
Coil spring
Left Side
Coil spring
Steerer tube
STKM
Length (w/o thread)
255
Length (w/55mm thread)
150, 180, 210
Crown race diameter
30, 27
Wheel size
26", 24", 20"
Brake
V-type
Preload adjuster
N/A
Note
Brazed on Disc mount bottom case available
Rebound Damping adjuster
N/A
 
You are great!
Thank you for the ideas!
Permalink Reply by Joe Torres on February 15, 2012 at 7:38am
Your bike is just over $200 new. Lee, don't dump money in this thing if that's the case.

The fork travel on your bike is 62mm assuming you have 26" wheels. I don't find a rigid fork with that correction.


Lee Rogowski said:

I'll look on Working Bikes, Thanks for the suggestion! I've been looking on CL.

I am going to the swap meet on Mar 3 to look for a different frame to build up. Is a 26" or a 700c better for touring? Because I have the investment in the SON dynamo hub laced into a 36 spoke 26" wheel suitable for touring, I'm leaning toward staying with a 26" frame and 26x1.4 tires. I've switched out to an 8 speed touring cassette with a new Schimano Altus derailer and have a Suntour triple chainring with a granny gear. These gears fit me very well on this bike.

In the meantime, I still have a Schwinn that fits me and that I've riden well over 3000 miles already. I've spilled it twice fully loaded and I've gotten hurt way worse than the bike! Its a tank.

On eBay there is a 25 cm threaded fork with 10 cm threaded. I can't tell what the suspension correction is or the length of the fork.

http://www.ebay.com/itm/BLACK-STEEL-1-1-8-26-MTB-BIKE-THREADED-FORK...

 

On my Schwinn Mira-Mar, I measure 42cm from axel to crown and 16cm for the steerer tube for the SR Suntour M2025 suspension fork.

These are the specs off the Suntour site (http://www.srsuntour-cycling.com/index.php?screen=sh.detail&int...) for my M2025 suspension fork. I'm not experienced enough to know how to read these and compare them to what is available for sale or even to what I've measured! I'd appreciate anyone who can interpret these for me!

Travel
63 (50) (30)
System
Coil spring
Lower
Steel
Design
Leading axle
Dustseal
Resin
Leg Color
Gloss black, Metallic silver, White
Crown
Alloy
Pitch
126mm
Integrated HD
Semi ID type / 43mm
Stanchion tube
STKM
Stanchion tube finish
CP finish / Miniboots
Finish
Black or Barrel
Right Side
Coil spring
Left Side
Coil spring
Steerer tube
STKM
Length (w/o thread)
255
Length (w/55mm thread)
150, 180, 210
Crown race diameter
30, 27
Wheel size
26", 24", 20"
Brake
V-type
Preload adjuster
N/A
Note
Brazed on Disc mount bottom case available
Rebound Damping adjuster
N/A
 
You are great!
Thank you for the ideas!
Permalink Reply by Lee Rogowski on February 15, 2012 at 8:14am

Thanks Joe! You are right, not to spend any money I can't take with me to another bike!

 

Looks like I'll be shopping around for a better bike to build on!

Permalink Reply by Far'arned Retrogrumpalunkus #63 on February 15, 2012 at 9:37am

I do not think that much weight is going to be saved with going to a non-suspension fork for the amount of money it would cost to do this swap.

But I would imagine that the amount of extra effort put into pedaling a suspension bike would be greatly improved by the fact that the shocks are GONE than any weight reduction realized by the swap by an order of magnitude -especially if the front fork is sacked out and needs a rebuilding anyhow.

Another option -which wouldn't address the weight issue but would get rid of the spongy see-saw would be to rebuild the front shocks with PVC pipe inserts where the springs used to be -fully removing any suspension travel or movement.  This would make the front end very stiff though as a regular fork has SOME flex in it and suspension forks are designed to have as little as possible.  It might be possible to stiffen up the forks substantually by removing half of the spring and replacing it with the appropriate length of PVC spacer.  

I quit the MTB world before suspension forks became very popular (or I could afford them) so I do not have any experience working on them but they do not differ all that much from motorcycle forks I would imagine.  Changing the preload (or even the over-all length/and sag) of motorcycle forks is done all the time using this method.  But if the forks are wore out and the seals or other parts need replacing in order to rebuild them this might get more expensive in the end too.  

Going with a new frame might be the way to go although I'm not sure what kind of components you have on there already and if it is at all worth swapping them to a new frame or buying a used higher-end frame with better components on them might be the way to go.  Sometimes the components on budget department store bikes are so low-end and disposable they don't even fit/work with better frames very well. 


Joe Torres said:

Your bike is just over $200 new. Lee, don't dump money in this thing if that's the case.

The fork travel on your bike is 62mm assuming you have 26" wheels. I don't find a rigid fork with that correction.


Lee Rogowski said:

I'll look on Working Bikes, Thanks for the suggestion! I've been looking on CL.

I am going to the swap meet on Mar 3 to look for a different frame to build up. Is a 26" or a 700c better for touring? Because I have the investment in the SON dynamo hub laced into a 36 spoke 26" wheel suitable for touring, I'm leaning toward staying with a 26" frame and 26x1.4 tires. I've switched out to an 8 speed touring cassette with a new Schimano Altus derailer and have a Suntour triple chainring with a granny gear. These gears fit me very well on this bike.

In the meantime, I still have a Schwinn that fits me and that I've riden well over 3000 miles already. I've spilled it twice fully loaded and I've gotten hurt way worse than the bike! Its a tank.

On eBay there is a 25 cm threaded fork with 10 cm threaded. I can't tell what the suspension correction is or the length of the fork.

http://www.ebay.com/itm/BLACK-STEEL-1-1-8-26-MTB-BIKE-THREADED-FORK...

 

On my Schwinn Mira-Mar, I measure 42cm from axel to crown and 16cm for the steerer tube for the SR Suntour M2025 suspension fork.

These are the specs off the Suntour site (http://www.srsuntour-cycling.com/index.php?screen=sh.detail&int...) for my M2025 suspension fork. I'm not experienced enough to know how to read these and compare them to what is available for sale or even to what I've measured! I'd appreciate anyone who can interpret these for me!

Travel
63 (50) (30)
System
Coil spring
Lower
Steel
Design
Leading axle
Dustseal
Resin
Leg Color
Gloss black, Metallic silver, White
Crown
Alloy
Pitch
126mm
Integrated HD
Semi ID type / 43mm
Stanchion tube
STKM
Stanchion tube finish
CP finish / Miniboots
Finish
Black or Barrel
Right Side
Coil spring
Left Side
Coil spring
Steerer tube
STKM
Length (w/o thread)
255
Length (w/55mm thread)
150, 180, 210
Crown race diameter
30, 27
Wheel size
26", 24", 20"
Brake
V-type
Preload adjuster
N/A
Note
Brazed on Disc mount bottom case available
Rebound Damping adjuster
N/A
 
You are great!
Thank you for the ideas!

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