Knobby tires and fenders

[Patrick Moore]

I am thinking of getting a second wheelset for the 2016 Chauncey Matthews "road bike for dirt" to supplement the very nice, very all-rounder-type 48 mm labeled/50 actual Soma Supple Vitesse SL wheelset. The second wheelset would have knobbies for sand, since the Somas just don't have the float and directional stability that I need for our sandy trails.

Riv content: I told Chauncey to measure my 2 (at the time) custom Riv Roads and make the new bike handle as much l like those as possible. (And with the Somas it does, wonderful; the 60 mm Big Ones wallowed and wandered --- not horrible, just not Rivendell-like -- tho' they floated well over sand.)

I am thinking of using RH knobbies -- since the reportedly once superlatively light and fast Thunder Burt has gained oz and stiffness compared to its first edition. (730 grams for the 700C X 2.35!! The 2.35 Big Ones are a digitally true 450 grams, and the F Freds that the TBs replaced were a true 360 at a true 50 mm.)

The 55 mm Fleecer Ridges (per specs ELs would probably measure very close to 60 tubeless on my 27 mm IW rims) for max float; but this would mean removing the Kelpie fenders. 

I like fenders. I live in the high desert with an average 9" of rain a year but we have a lot of dust and full fenders keep a great deal of it off my legs and off of the bike. Also, the Matthews was one of my 2 "rain bikes" -- puddles and snow melt included.

I used these fenders with 60 mm Big Ones, but those were smooth tread and even so barely cleared under the seatstay bridge; about 5 mm.

Obviously, using ~60 mm knobbies with these fenders would be foolish, and I've been thinking that perhaps the Oracle Ridge might work with them, at barely 50 mm extrapolated from the website; the 50 mm Somas have perhaps just shy of 2 cm of clearance at that tight spot under the seatstay bridge and 3 cm+ under the fork crown. (The Big Ones measured ~29 1/2" tall, the Somas ~28 1/2" tall, so 1/2 inch/~12mm difference.)

So I'm curious if any of youse use fenders with knobbies and:

1. What is the minimum gap your require?

2. how big are the knobs? IOW, are small, even knobs as on the RH knobbies safer with fenders than the big fat knobs on real mtb tires?

3. What do you say in particular to ~50 mm Oracle Ridges under full fenders with the clearances described?

I cannot use the aftermarket stay breakaway systems because the Kelpie stays are 50% fatter than the stays they were designed for.

4. If I don't use full fenders I will certainly install "motocross-style" fenders, but those I've seen are fugly. 

4.a) Are there non-fugly clip ons? 

4.b)Share photos?

4.c) Source/link?

Thanks.

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Patrick Moore

Alburquerque, Nuevo Mexico, Etats Unis d'Amerique, Orbis Terrarum

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[George Schick]

Patrick: yes to several of your requests. But I don't want to clutter up this blog with photos so I'm sending you a PM with them attached.

[Patrick Moore]

George, thanks, I'll look with great interest at your later posts.

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[ascpgh]

Seems like a similar question to the fenders off road (with smooth tires) question and maxims.

I've got no knobby tires as of yet. I've ridden both my Rambouillet and Coast rando off road and only find the front mudflap an issue. I use two small bulldog binder clips  to affix the flaps (with their handle bales removed once mounted) and take them off when surface conditions are such that I'm picking things up at a rate higher than a low grade nuisance. I'm not riding at speeds high enough to cause any drama worth posting on social media. 

If my conditions and riding reach the point of requiring greater traction I would be all over the appropriate sized RH knobs for having dimensions that match those of the slick (file tread) tires for easy clearance consideration instead of beta testing all that myself with others' inputs. 

After Bill's brevet report I'm eagerly anticipating a long ride down the GAP which ihas n the past included some snowpack near the divide and plenty of recently unfrozen limestone dust trail surface that gets a bit spongy and slightly wheel spinny if trying to push yourself. They have a very nice uniform low height to width knob profile so they don't wobble under pedal or steering input. I learned about that with OG Specialized Hardpack 26" x 2.2"  riding trails off the Continental Divide in south central Colorado, 1988. Flexy knobs, taller on the sides, will let you down. Abruptly. 

Andy Cheatham

Pittsburgh

[Tom Wyland]

I'm not sure if this answers the question but perhaps it will help. I run 63mm VO Fluted fenders on my Platypus.  The stated max tire size is 48mm with fenders.  I have the smooth RH Hatcher Pass (48mm) on Velocity Dyads (so they measure closer to 45mm but greater diameter). I switched to knobby Oracle Ridge tires of the same size, and my fenders rubbed on my rear light mounting bolt (inside the fender). So they do require greater clearance for the tire only. I just had to make a very slight rear stay adjustment (2mm) to keep the tires from rubbing.

In general though I prefer at least 10mm of clearance for non-knobby tires. I mostly just do the fender width minus the stated tire width instead of dealing with measuring the gaps everywhere.  So 63mm-48mm is 15mm of stated clearance.

Tom

[Steve]

Not a direct comparison, but I can share that I've run 42mm Knobbies (WTB Resolutes) with both 52mm VO Zeppelins and 58mm Tanaka smooth fenders. I also ran a pair of 40mm Continental Terra Speeds (low profile knobs) under the Tanakas. Each of those combinations would occasionally kick leaves and small  sticks up into the front fender when riding gated fire roads, sometimes necessitating a stop to clear the debris. My turf, however, is woodsy Appalachian national forest -- a bit different from Patrick's high desert.  

This past autumn when the leaves began to fall I pulled the fenders off my 'dirt bike' and mounted the largest tires the bike would accommodate; 48mm RH Oracle Ridge knobbies. I've been delighted with the bigger tires. The fenders have been safely stored away, waiting for the day when I decide to mount some 38mm RH Barlow Passes on it, swap the upright bars for drops and take it on the road.

Steve in Asheville

[Michael Kashuba]

Another data point…..I’m running 700 X50mm (actual measurement is 48/49mm width) SOMA Cazaderos with VO fluted 63mm fenders on my 60cm Appaloosa. All is fine clearance wise as long as I don’t mud up…☺️

Mike in Fair Oaks, CA

Sent from my iPhone

On Jan 30, 2024, at 7:41 AM, Steve <steve...@gmail.com> wrote:

Not a direct comparison, but I can share that I've run 42mm Knobbies (WTB Resolutes) with both 52mm VO Zeppelins and 58mm Tanaka smooth fenders. I also ran a pair of 40mm Continental Terra Speeds (low profile knobs) under the Tanakas. Each of those combinations would occasionally kick leaves and small  sticks up into the front fender when riding gated fire roads, sometimes necessitating a stop to clear the debris. My turf, however, is woodsy Appalachian national forest -- a bit different from Patrick's high desert.  

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[Patrick Moore]

Thanks Steve and Mike. Question: Do you use a QR strut system with your fenders or do you feel confident enough to use your VO Zeppelins and Tanakas and VO Fluted fenders with direct, bolted stay connections to frame and fork?

I have no problem using fenders over non-knobby tires; I did this with the Big Ones with, again, smaller than canonical clearances under crown and certainly under seatstay bridge, but I am much more wary of doing this with knobby tires.

Again, my safe choices seem to be: Fleecer ridge (~60 mm) for max sand float but without fenders, or (~50 mm) Oracle Ridge under the fenders, which I'd like to keep on the bike.

Re fender QRs: Even if I could find some to work with the much fatter Kelpie stays, these fenders and stays are so sturdy -- stays and fenders 50% thicker gauge at least than VOs and Honjos -- that even with QR stays I'd still be very wary of having a stick slam the front wheel to a stop. Anecdote: Colin at Kelpie first offered his fenders in titanium but after he picked up a stick and jammed his wheel, and damaged his fork but not his fender, he started using thick gauge aluminum so that the fenders might break before the fork does. But even so, these fenders are so sturdy that I'd be very reluctant to risk a stick on the front tire with less than optimal clearance.

So the question remains: 3+ cm over an Oracle Ridge?

On Tue, Jan 30, 2024 at 8:41 AM Steve <steve...@gmail.com> wrote:

Not a direct comparison, but I can share that I've run 42mm Knobbies (WTB Resolutes) with both 52mm VO Zeppelins and 58mm Tanaka smooth fenders. I also ran a pair of 40mm Continental Terra Speeds (low profile knobs) under the Tanakas. Each of those combinations would occasionally kick leaves and small  sticks up into the front fender when riding gated fire roads, sometimes necessitating a stop to clear the debris. My turf, however, is woodsy Appalachian national forest -- a bit different from Patrick's high desert.  

This past autumn when the leaves began to fall I pulled the fenders off my 'dirt bike' and mounted the largest tires the bike would accommodate; 48mm RH Oracle Ridge knobbies. I've been delighted with the bigger tires. The fenders have been safely stored away, waiting for the day when I decide to mount some 38mm RH Barlow Passes on it, swap the upright bars for drops and take it on the road.

Steve in Asheville

[Patrick Moore]

I should have added as context that while I ride in sandy conditions, I also ride in our riverside bosque with thickly scattered cottonwood debris scattered over many of the trails.

[Steve]

Patrick, to your QR question,  I've run fenders over knobbies on my Ritchey Outback (clearance ranging from ~ 15 to 20mm depending on the fender/tire combo) with and without QRs.   After bending a front fender stay with a jammed stick I took the hint and added a pair of Portland Design Works Safety Tabs. Before I finally pulled the fenders to accommodate larger tires for that bike I put the Safety Tabs to the test (x 2). They work!  As an aside, the larger tires I mounted are Oracle Ridges - love 'em! 

The PDW tabs are designed in two parts - a metal sleeve which is secured to the stay with a set screw and a plastic bracket that bolts to the fork mount. The two parts are jointed by a "pop off" barb on the plastic bracket. I'm guessing you could bore the sleeve out to fit your larger diameter stays if you want to give them a try.  Worst case - you might need to epoxy the sleeves to secure them to the stays if they wind up too thin walled to use the set screws. 

Regarding running  knobbies with 3+cm of fender clearance  (that's HUGE!):  there's only one way to know for sure

Steve

[Patrick Moore]

Thanks, very good suggestion about modifying the PDW tabs. Will take a closer look at them and compare their ID with my stays' OD. One possible complication is that the leftside front fender stay is bent to fit under the disc caliper which might compromise fit of the plastic bracket. I'll have to weigh this against shortening the fender and running stays to the lowrider bosses.

On Sat, Feb 3, 2024 at 7:58 AM Steve <steve...@gmail.com> wrote:

Patrick, to your QR question,  I've run fenders over knobbies on my Ritchey Outback (clearance ranging from ~ 15 to 20mm depending on the fender/tire combo) with and without QRs.   After bending a front fender stay with a jammed stick I took the hint and added a pair of Portland Design Works Safety Tabs. Before I finally pulled the fenders to accommodate larger tires for that bike I put the Safety Tabs to the test (x 2). They work!  As an aside, the larger tires I mounted are Oracle Ridges - love 'em! 

The PDW tabs are designed in two parts - a metal sleeve which is secured to the stay with a set screw and a plastic bracket that bolts to the fork mount. The two parts are jointed by a "pop off" barb on the plastic bracket. I'm guessing you could bore the sleeve out to fit your larger diameter stays if you want to give them a try.  Worst case - you might need to epoxy the sleeves to secure them to the stays if they wind up too thin walled to use the set screws. 

Regarding running  knobbies with 3+cm of fender clearance  (that's HUGE!):  there's only one way to know for sure.

That's with the Oracle Ridge. I'd like to use the Fleecer Ridge which would reduce clearance to about 20 mm.