BigDB67

The steerer tube is the part that attaches to the stem. Spacers and cutting can match whatever geometry you have/want.

How to cut down a fork steerer tube - BikeRadar USA

PSYS

ahhhhh..... I'm with ya!
I was under the impression that the aftermarket fork has to match the same axle to crown of the current fork that came stock on my bike?

BigDB67

It does, the stem has nothing to do with that measurement though!

https://fcdn.mtbr.com/attachments/sho...rs-sid-a2c.gif

https://www.bikecad.ca/faqFiles/fork_...ork_length.png

gpburdell

PSYS - somewhat counterintuitively the "crown" is at the bottom of the steerer portion and not at the top. See Bicycle fork - Wikipedia, the free encyclopedia

Ayers

In my case, I went to bikepedia and looked up my bike. It showed my front fork as a 100mm fork.

Surly showed three options for the 1x1 fork for 100mm suspension correct application. There was the cantilever brake option, cantilever and disc option, and disc only option. I chose the disc only option which made it a bit harder to find. Apparently it's the least common stocking part number of the three options. I'm a bit particular and didn't want to settle for buying the common (disc and cantilever application) fork since it would have left me with two unused cantilever brake bosses on the fork which would have annoyed me. Ultimately I found it in stock at Universal Cycles.

https://www.universalcycles.com/shop...2&category=703

side_FX

What model Trek is this? Do you have a shot of the whole bike showing how the fork looks in proportion to the frame, color, etc.?

manc

470mm axle to crown measurement is about right for Trek DS

Ayers

Mine is a 2009 4300 disc.



It's a real turd but I'm partial to the bike since it was what I started off on as I got more serious. I say this bike is worth 40 pounds because that's how much weight I lost riding it before I met my personal goal and stepped up to a true quality road bike.

i keep it around to ride with my wife. She's a casual hybrid bike rider and I need something to ride at her pace without the hassle of shoes and shorts and all the road bike garb I usually wear on my solo rides.

side_FX

Thanks for pic! That's no turd, it looks like the perfect setup for the type of ride you mentioned.

PSYS

FYI...... The Surly 1x1 fork will not work with the Trek DS series. The Surly 1x1 is for 26" wheels/tires. The Trek DS series uses a 700c / 29'er.
I believe as MANC referenced above, the axle to crown of the 8.2 DS el cheapo Suntour non-lock out is approx. 470mm.
I spoke to my LBS and they're checking to see if the Surly Ogre fork will work with my 8.2 DS.

Ayers

Did they say why the a Surly fork wouldn't work ? I'm guessing it has something to do with brake rotor position ?

It made me curious so I threw a 700 under my bike. It fits fine, but I can't speak to brake rotor issues since I only have rim brake 700s around here.

PSYS

That is so bizarre.
They said the Surly 1x1 is only recommended for 26" wheels and not recommended for 29" / 700.
They said my 700 x 38 tires would not fit. ugh. This is incredibly frustrating.
I don't have disc brakes. I have cantilever / rim brakes.

Ayers

I'm sure the position of the brake mounts are what they're referring to. I guarantee you the tire size is a non issue. That's a 700x25 Gatorback tire in the picture and there is stupid amount of clearance in all areas.

corwin1968

Check out the Surly Ogre fork. It's 470mm and has cantilever studs.

JG1967

Pics and measurements of the replacement RST Vita fork from my Trek 8.5 DS. Measurements are in inches. This should give an idea of the size rigid fork needed for a Trek DS Hybrid. My bike is a 2012 vintage.

PSYS

Thanks for taking the time to do this!
This does help...

PSYS

Thanks for this... this is the third recommendation I've had for the Surly Ogre.

I called my LBS on my lunch break today at work and tried to settle this once and for all.
They said the following:

According to Trek's website, the offset on my bike is 38mm which they said is fairly small according to the industry 'standard' for 700 / 29'ers.

The Surly Ogre has an offset of 43mm. This is a fairly insignificant difference, BUT it could very well affect the handling. They said the 43mm of the Ogre being slightly longer could make the steering of my bike feel slower.

They could not think of any other 38mm offset rigid suspension corrected forks to recommend.
I'm blown away that with all the searching I've done, I've not found more information about this.
I would think this would be a fairly common upgrade from the el cheapo Suntour junk that came on the DS.
I'd rather have a quality rigid fork than the cheap suspension fork any day.
It boggles my mind that I simply can't find more options out there.

I feel like I'm missing something.

Do I just go with the Surly Ogre?

JG1967

My pleasure! I'd say a fork with an axle to crown measurement of 470mm to 480mm will work. Any shorter than that and the geometry will be thrown way off.

Ayers

Surly Ogre fork. In stock and ready to ship....

https://www.universalcycles.com/shop...8&category=703

JG1967

Have no idea what this costs but it looks perfect for what you want.

Forks | Whisky Parts Co.


No 7 Carbon QR 29er Fork

[h=2]465 A-C / 640GR / 39 OFFSET / DISC[/h]1.125” - 1.5” Tapered carbon steerer S.H.I.S. - Clamp 28.6 - Race 40
9mm QR Dropouts - 100mm spacing
Post mount disc (160mm-185mm)
95mm width between fork legs - 3.8 tire on a 65mm rim (max)
80mm Suspension corrected
UD full carbon construction
No rider weight limit
5 year Whisky warranty
ASTM Condition 3 - For rough off-road riding and jumps less than 24"

corwin1968

If the Ogre fork is a little longer (I didn't catch what your fork's actual measurement is) it will slow down the steering, slightly but the increased rake of the Ogre fork will offset that to some degree. I will say that 5mm of offset difference isn't going to make a huge difference. You might feel it, you might not but it's not going to make the bike unrideable. There are online calculators that will tell you how much a longer fork will change your head tube angle and then it's just a matter of plugging the numbers into an online trail calculator and you can get a pretty accurate idea of how much the handling will change.

EDIT: I looked up the geometry for the DS and if the 19" fork length in JG1967's photo is correct for the stock fork then changing to an Ogre fork will change the bikes trail from about 81mm to 83mm, which is totally insignificant. It will change the bike's wheel flop from about 25mm to 27mm. Wheel flop is just the tendency of the wheel to fall to one side or the other at very slow speeds or when stationary. Both the trail and wheel flop of the DS are very high already, which is very common for off-road bikes.

There's no guarantee that an Ogre fork will be an acceptable solution but the numbers make it look pretty reasonable.

I would get an estimate on price before pursuing it. I know nothing about suspension forks but the Ogre fork will need a crown race and a star nut, as well as spacers and a cap/bolt for the top. Also make sure your current headset will work with the Ogre fork. Headset/fork interchange dimensions are beyond my knowledge so you'll have to ask your LBS to make sure what you have will match an Ogre fork, otherwise you might need to buy a new headset as well. I would say the cost might easily hit $200 before all is said and done.

You might be better off just upgrading. A Trek FX model will do just fine for the riding you described.

Ayers

You will need a new star nut which is like 2-3 bucks. There's no reason not to reuse your crown race and all of the headset and spacers and all of that.

The change in geometry is pretty insignificant on the handling. Any changes you'll notice will be mostly from dropping so much weight off of the front of the bike. It really perks up the performance.

PSYS

I bit the bullet this morning and ordered the Surly Ogre. If I find the bike rides too unpredictable or I don't care for the handling - my worst case scenario is I need to go back to the stock suspension fork and return the Ogre.
I can live with that. I am hoping based upon the numbers and everyone's two cents worth, this works out for my situation.
I shall keep all of you posted.

Thanks again to all of you guys who chimed in and took the time to post photos...

- scott.

steve_cay

Another option (if the Ogre does not work out), is to get a "proper" locking fork, that was designed for these types of bikes. A Rockshox Paragon at the high end, or a Suntour/RST at the mid end. Although they may add 2lbs to the lightest non-suspending forks, locked is as firm as it gets, and you can still open it up for a suspension over trails. Just make sure it has the mounts for your non-disc brakes.

PatrickGSR94

I think you'll be fine. I chucked the old RockShox suspension off my late 90's MTB in favor of a Nashbar chromoly steel height-corrected rigid fork a couple of years ago, and never looked back. It has disc tabs, and removable V-brake bosses. I just ordered an Avid BB7 disc brake and front wheel, so I'll be removing the brake bosses when I swap out the wheel and brake.

Nashbar Rigid Mountain Bike Fork