I just got a Grail 7 AL and tossed on some Gravel King Slicks 27.5x1.5 as that's all the XS frame could handle. Coming from the G-One Bites that came on the bike to these, I feel like the front end tends to pull to each side with the slightest amount of input from the bars. Has anyone else noticed this or is it that I have these tires on backwards?
There is not directional markings on them which make me guess they wouldn't be? I pointed the V facing forward but am wondering if anyone has ridden these this way vs flipping them around and seen any differences?
The below image is the front tire facing forward (from the perspective of being on the bike). I wonder if flipping the tire so that the angled patches outside of the middle would be facing the other way would feel different?
Do you mean the V starting from the middle of the tire? This is looking forward on the bike so the full V on the outsides of the tire point forward but from the middle of the tire, the first half of the V points backwards.
It also confuses me that there is no directional marker on these 😁
I may try to flip the front around to see if I notice a change in handling and report back.
Indeed if UP is FORWARD in the pic it's expected that the tire will "tramline" (in auto tire parlance). May be useful in autocross, but be too twitchy to ride straight. Reverse 'em!
It relates to tires that tend to follow off-axis pulls in pavement from ridges, paint, rr tracks, etc. Somewhat correlated with width, of course, as a narrower tire wants to go straight, following caster and momentum regardless of road irregularities. Old stupid V-tread auto tires are notoruious for tramlining if driven "backwards"...as well hydroplaning, of course.
Hmmm..... off to check my tires... had no idea these were directional, but my bike does tend to behave oddly on turn-in with the 700c GK+ slicks. I figured it was geometry... my 650b tire/wheel combo doesn't do it
I'm not sure direction is the reason for tramlining. When you're going straight you're on the center file tread which is not directional.
I've noticed tramlining with the GK+, GK-SK+, RH Snoqualmie pass, and Soma SV. It might have something to do with the casing or the rubber since those tires are similar and made by Panaracer.
I haven't noticed any tramlining with Shikoro (also made by Panaracer but with a thicker casing and harder rubber), G-One Allround, Marathon Almotion, GP5000, Taraxagum, Cinturato Gravel H, or Strada Biancs Pro.
I vote for @stu to be correct. I just checked both my wife's bike and mine. Out of 4 tires, all of them are mounted "backwards". I am curious though.... if the direction of the "siping" does matter.... why is it one direction and then the other further down the tread???
Waiting patiently for @miloiii123 to report back. I'm too lazy to change a bunch of tubeless tires without knowing for sure. 😆
The tramlining I've experienced has been more when starting turn-in. The second I turn at all, it feels like the tires want to pull away instead of stay upright with any speed. I didn't experience this sensation with the g-one bites that came on the grail but noticed right away on these. Also at speed I almost never feel like I have much stability when turning.
Going to a friend's after work to flip them around and maybe that'll help. If I still experience the same, I'll chalk it up to the casing and compounds as this is my first Panaracer tire.
So flipped them around this afternoon after making sure I had enough sealant in them. It does seem like the tramlining is much less pronounced now. I only went around the block but it seems a little more stable and that any time I initiate turn-in, the front does not want to pull to one side.
I’ll test some more tomorrow when I go for my lunch ride!
TheSubaruGuru wrote:Indeed if UP is FORWARD in the pic it's expected that the tire will "tramline" (in auto tire parlance). May be useful in autocross, but be too twitchy to ride straight. Reverse 'em!
I consider “forward” to be the direction of rotation. Pretty much the standard for bicycle tires
stu wrote:I'm not sure direction is the reason for tramlining. When you're going straight you're on the center file tread which is not directional.
I've noticed tramlining with the GK+, GK-SK+, RH Snoqualmie pass, and Soma SV. It might have something to do with the casing or the rubber since those tires are similar and made by Panaracer.
I haven't noticed any tramlining with Shikoro (also made by Panaracer but with a thicker casing and harder rubber), G-One Allround, Marathon Almotion, GP5000, Taraxagum, Cinturato Gravel H, or Strada Biancs Pro.
There are several reasons why a FOUR-wheeled vehicle will tramline, including tow-in, tread style, and of course, if directional tread is run backwards...and dangerously if "V"-shaped in the rain, as hydroplaning develops very quickly. Impressed with your experience on bikes, inc that SOMA SV tramline, which I haven't experienced. I'm more apt to guess that tread patterns are a bigger factor than carcass compliance, but maybe it gets complicated by pressure too. Nonetheless cannot imagine a time I'd run "V"s backwards!
My Soma SV didn't tramline as much as the others and that may have been a different effect. Most of my SV miles were with the 48 mm version on a 21 mm rim, which was probably too narrow for that tire on pavement. The 42 mm SV exhibited better stability.
The GK-SK+ and Snoqualmie Pass have obvious tangential grooves which may contribute to tramlining. I'll have a better idea when I wear down the center tread of the Snoqualmie Pass. The GK+ file tread is very close to having tangential grooves, at least when new. Again I'll know more if I ever wear that down.
My other tires, which don't tramline, do not have tangential grooves.
I'd be shocked if that minimal tread pattern had any real influence on bike handling. The tram-lining feel that you're describing is similar to what I feel when I run my front tire at low pressure. I'll sometimes air my 37mm GK SK down below 30 psi when I'm in deep gravel, and when I get back on the tarmac it really feels like the bike doesn't want to come back up to a straight line after I lean it into a turn. I pump it back up above 30 psi and the handling returns to normal.
I have experienced tramlining with: 40 mm GK+ from 40 to 50 psi 43 mm GK-SK+ from 35 to 45 psi 44 mm Snoqualmie Pass Endurance from 35 to 45 psi
I have not with: 32 mm GP5000 from 50 to 60 psi 35 mm Taraxagum from 45 to 55 psi 36 mm Strada Bianca Pro from 40 to 50 psi 40 mm G-one from 40 to 50 psi 40 mm Marathon Almotion from 40 to 50 psi 42 mm Shikoro from 40 to 50 psi 45 mm Cinturato Gravel H from 30 to 40 psi 48 mm Shikoro from 30 to 40 psi
I'm not sure with these, I haven't used them for a long time and they were on narrower rims but don't remember serious tramlining: 38 mm Barlow Pass Extralight around 55 psi 42 mm Soma SV EX around 50 psi
Those pressures are probably a little high for gravel. I haven't tried lower pressures because I want to avoid pinch flats and rim damage. The Cinturato Gravel are big enough I could try the front at 20 or 25 psi on smooth, grooved pavement to see what happens.
