Andy Bayley's Studded Tires
I'm going to copy the article that I posted on the Subaru forum with my results. I'm also going to add a few comments on my experience with
racing on "get - by - spares" which I ran on my Talon TSi two years back.
First off, a BIG thanks to Jeremy Butts. I couldn't have done this without his knowledge or help!
From the Subaru
Here are thoughts and suggestions on how everything went:
First of all, the traction of a good "pick" tire cannot be compared to anything... period!!! A well built pick tire on glare ice will hold
better lateral G-forces than a racing slick on tarmac. Anyone who tries to say otherwise, has most likely never ridden in a pick tire car. While a
"studded" snow tire is noticeably better than your average non-studded
snow tire, a home made pick tire is an entirely different monster that is not even in the same league as something like a pre-manufactured studded
snow tire. There is a company out of Sweden (I think) that makes Rally Specific Ice racing tires, but even those perform, at best, on par with an
average pick tire. Also, anything labeled "Rally" demands a premium from the check
My tires I made cost me about $250 each. This price included everything from the wheel to the tire sealant. The first thing I needed to do was
find a wheel that would work.
I decided to go with a 15" wheel on my 2004 WRX. A 15" wheel is pretty much necessary in order to gain the extra clearance caused by the protruding
bolts. I wanted to make DAMN sure I wasn't going to have any bolts eating their way through my inner fenders walls. This obviously created a big
problem due to the lack of inexpensive 15" rims to be found. However, I was able to convince a Group N SCCA Pro Rally friend of mine to let go of
four Raceline RL-7's for $100 each. The next step was to get the lowest profile 15" tire I could find. I really wasn't too concerned about getting a
narrow tire, since the race is supposed to be on glare ice. The more picks that dig into the ice, the better the traction. With that said, a wider tire
isn't necessarily a bad thing for ice racing with picks. I decided to go with a set of 205/50R15 on all four corners. I was able to get Tire
Rack to send me out a set for $50 per tire.
Next step was to acquire the hardware needed to produce the picks. I went with a grade five 1/4" diameter bolt that was 1 inch long. To keep the
bolt in place, fender washers were used on both the inside, and outside of the tire. To secure the bolt, self locking nuts were used on the bolts.
Each bolt assembly (1 bolt, 2 fender washers, 1 locking nut) came out to $0.25 per assembly. Estimating 200 bolts per tire, the price for the hardware
came out to about $200. Add a $25 mounting fee per tire (forget balancing!!!) and some tire sealant (i.e. tire slime), the price comes
out to about $250 a tire.
When making the tires, the first thing I did was lay out a tread pattern. I could have used any set of old, bald tires. However, since the
205/50/R15 were such a rare sized tire for my area, I had to buy new tires (at $50
a piece... no big deal). The pattern I went with were alternating rows of 2 bolts, and 3 bolts with each row paced an inch apart.
After marking off the bolt locations, I used a drill with a 1/4" bit to make the initial holes for the bolts. Next, I would take each bolt,
cover it in windshield adhesive then run it through the hole I recently drilled.
I would usually run about 30 - 40 bolts through the tire before I would stop and put the lock nuts on and torque them down. With all the bolts
in place and tightened down, I would then run the wheel and tire over to the tire shop and have them mount it. Again, balancing is NOT going to
happen on these tires. It would be pointless to even try.
Once all the bolted tires are mounted, the protruding ends of the bolts need to be sharpened. The sharper the picks are, the more effective the
tires become. I've seen people run out of time towards the end of the process and not sharpen their bolts. The results of their tires were
significantly less than those of a well sharpened tire.
The way I sharpened the tires was by using a snowmobile stud sharpener. It's a really neat little tool that guys have been using for years to
sharpen their studs on snowmobile tracks. It's a round cutting fixture that holds four hardened carbide (sp?) blades that fit onto the end of a
drill. The cutting fixture is placed over each individual bolt and sharpened to a
point. They make different angle's of sharpening tools, but I was only able to get the 45 degree tool to fit over the 1/4" diameter bolt. The 30 degree tool would not fit over the bolt (tool opening was too narrow). So all those picks you see in the second picture posted above started their
life as simple 1/4" bolts, not snowmobile studs. (*e-mail note - a lot of people thought my tires had snowmobile studs in them from a picture
attached in a previous post)
As far as sealing the tires, I really didn't have to do much of anything. The windshield adhesive took care of most problems from the get go. I
only had one tire that was leaking any air, and that was very minimal. It would go from 30 psi to 20 psi after two days. Any pick tire that holds air
for an entire race (i.e. 5 minutes) is considered to be a success by most. However, just to play safe, I dumped about 16 ounces of "Tire Slime"
into each tire to guarantee a good seal. I filled the tires up to 45 psi on Thursday night, raced all day Saturday and they are still holding 45
psi as of Monday night. A tube for the tire is not needed in my opinion. Also, the
rough head bolts would most likely tear apart the tube apart anyway.
Driving on picks is an experience unlike anything else. It is a very awkward feeling. It will constantly feel like the tires are flat.
Basically, the picks will pull the tires around looking for the deepest ice. On perfectly glare ice, it's not that bad. However, on a rutted up
course, the tires are going to pull in all sorts of directions. You need to be a very aggressive driver with a heavy hand on the wheel to make these work for you.
One thing that does suck about these tires is the snow traction. A lot of the rubber tired guys were intentionally running into the
snow banks on the course in effort to give themselves more traction. While this helps for
the rubber tire guys, it really hurts the pick guys. If the picks don't dig down into ice (i.e. riding on top of snow) they will not hook up any
better than your average snow tire. Going from +1G of lateral grip to < 0.05
G's on a snow surface at +75 mph can quickly become a handful. Especially if the snow patch is small and quickly followed by more ice. It's sort of
ironic how a picked tire driver responds the exact opposite to a rubber tire driver (Picks: ice = good, snow = bad).
As far as vibrations, it's really hard to tell. You're beating on the car so badly, the only noises vibrations you are really listening for are
the fatal ones: BANG! CLANK - CLANK - CLANK! SKREEETCH!!!
Each tire probably took about 5 hours to make including sharpening time. I started construction on them Monday after work, and had the final tire
sharpened by Saturday night. So I guess 20 hours sounds about right.
As for top speed, the course was pretty slow and tight and only 1/2 mile in length, but I still think I saw 75 mph in a few areas (2nd gear hitting
(My own input regarding racing on "get - by -spares")
During the 2002 race, I decided to use a set of 15" get by spare tires with "Cold Cutter" Ice screws sold through Dennis Kirk
Racing products on my 1991 Eagle Talon TSi (AWD Turbo). Each tire was prepped with 250 screws. I will say that I had a more difficult time getting
the biased ply spare tires to hold air with the ice screws when compared the steel belted radials I used for my pick tires. The spare tires would
leak from 60 psi to about 30 psi over 15 minutes. Is all fairness though, I did
nothing to the spare tires to get them to seal before the race (no tire slime or fix a flat). Each tire probably took about 1 - 1.5 hours each
The performance of the screws was "good". Looking at the results of the 2002 event, the fastest 4WD rubber cars were 50 - 52 seconds while my
fastest time was 40.82 around the track. However, a 2WD picked tire car raised the bar for tire selection by beating my best time by over two
seconds (38.73) Of course, neither vehicles were able to compete with the open class sleds / bikes which were putting down times in the low 30
The one thing I noticed about the spare tires was the very weak sidewalls. With just the ice screws, I could easily feel the tires starting to
fold over. This was with 60 psi of air pressure as well. It is suddenly becoming more and more apparent why Soren's picked spare tires were
ripped off the beads at only 30 psi. I was also able to look a few photo's from
the 2004 event where my WRX was shown taking a corner very rapidly. Even at 45 psi, my steel belted pick tires looked as though they were getting ready to be torn off the wheel as well. I'm starting to think that a
major part in why Jeremy's pick tires performed better than mine was because of the heavy duty sidewall of the Rally tire. I simply used a generic all
season Kuhmo while Jer used an old set of Rally Tires. However, Jeremy seemed to have a few studs break off last year due to the extreme cold
of Northern Minnesota and the hardness of the rubber compound found in Rally
tires. To be fair though, Jeremy's Rally tires had already seen multiple races on them before breaking. We'll see how well mine hold up.
That's about it for my input, I can't wait to see what people show up with next year.
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