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 On Tuesday, January 30, 2024 at 2:16:38 AM UTC+1 ascpgh wrote: > 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 > > > > > > On Sunday, January 28, 2024 at 4:36:55 PM UTC-5 Patrick Moore wrote: > >> 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. >> >> >> >> >> >> -- >> >> Patrick Moore >> Alburquerque, Nuevo Mexico, Etats Unis d'Amerique, Orbis Terrarum >> >> ------------------------------------------------------------------------------------------------------- >> >> Executive resumes, LinkedIn profiles, bios, letters, and other writing >> services >> >> >> ------------------------------------------------------------------------------------------------------- >> >> *When thou didst not, savage, k**now thine own meaning,* >> >> *But wouldst gabble like a** thing most brutish,* >> >> *I endowed thy purposes w**ith words that made them known.* >> > -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. To unsubscribe from this group and stop receiving emails from it, send an email to rbw-owners-bunch+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/rbw-owners-bunch/bf333594-e34b-482c-8d5f-e1802ec13fb2n%40googlegroups.com.
