Vermont Grand Fondo - tire selection

Hi,
I am training to do the Vermont Grand Fondo this year. Here are some stats about the ride:

distance: 109 miles
climbing: 10,500 feet over 4 significant gaps (10-15% average and grades up to 25%)
gravel surface (hardpack dirt road conditions): 27 miles (remainder paved)

I ride a Serotta road bike (Ti frame) and usually ride Continental Grand Prix 5000 tires (clinchers). I can only run 25 mm in the rear (clearance) and run a 28 up front.

Seeing that this is a unique ride profile, including tons of significant climbing, yet also including a significant amount of hardpacked dirt road I am wondering what tires to run? Based on all the climbing I would prefer something somewhat light (fast rolling) yet would like something with a bit of extra grip for the dirt. I realize it is greedy to expect the best of all worlds, but figured there has to be a good compromise tire that may check these marks reasonably well. So I want something super light weight, that rolls with the fastest race tires, with crazy grip on all surfaces, and incredible durability to handle all road surfaces :smiley:

my searches were popping possibilities such as:
Specialized Roubaix Pro
Vittorio Rubino Pro Control
Continental 4 season

Anyone have any suggestions based on experience?

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I’m from VT and I’ve ridden those roads many times! GP5000 tires will be perfectly fine for you. I like 28mm if you can fit them.

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Im in the area. I would rather be on something like 30’s. But you will be perfectly fine on most road tires. I would go for durability so you could run slightly lower pressure. But thats just me. Most the steep stuff is paved on that route, so grip wont be a huge concern. Everyones ridden D2R2 on road tires over the years, and that generally has a lot more steep dirt roads than this (if the routes are similar to the old ones).

@BTTG @ZDW1995 @scurran I’m so glad I found this thread! I’m registered for the VTGF, and would love to make my existing Ti bike work.

I too have an “old-school” set up, and the main issues I’m trying to solve are gearing and tire width.

Gearing
My stupid short cage rear derailleur can’t take more than a 28 tooth ring on the back. I think it won’t be hard to remedy that with a new derailleur, but I’m still stuck on the tire question.

Tires
I have Ultegra caliper rim brakes that can handle 28mm tires and maybe could take 30s, but it’d be tight, and with relatively narrow rims, the profile of the tire will be pretty “lightbulb-shaped.”

It sounds like from your comments that I might actually be okay. I was prepared to upgrade to a whole new bike with all the fancy new things — carbon frame, tubeless tires on wide carbon rims, 105 Di2, blah blah blah — but I am very attached to my titanium frame.

Any help or confirmation you can provide on tire selection would be greatly appreciated! Trying to have it all sorted out in the next few weeks, because if I do need to pursue a new bike, time is of the essence!

Thanks.

With the steep pitches, you’re going to want more tire. You might end up walking them either way.

I’d also worry about washboard on the dirt roads, but you’d need MTB size tires to deal with that. Riding on Michigan groomed dirt roads, 28c tires were fine, but I stopped and cried after hitting a washboard on a short downhill on 40c tires. Potholes filled with soft material are another area where a bigger tire will shine.

Any regular road tire should be fine, but I’d definitely go tubeless for the lower pressures and to prevent pinchflats. Just use your GP5K, the other tires won’t do anything for you.

Maybe use this as an excuse to get a gravel bike.

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Yo! Glad you found it too. Stoked to hear you’ll be doing the VTGF!

28t cassette in the rear is doable, but if you can swap the cage or the whole derailleur for long cage, 32 (or even 34 these days) is preferable for the climbs on the course. There are some steep pitches and being able to hold a comfortable cadence definitely helps out!

28mm tires will be okay for you – I’ve ridden all those roads on 25-28mm (even 23mm at one point!) without any trouble. Vermont dirt roads are actually quite smooth and often better than paved roads in some parts. Washboarding isn’t super common, and when there is washboarding, it’s usually not that bad. If you could go tubeless, I do think it would be worth it, but that is more for the benefit of sealant in case you get a puncture. For what it’s worth, I’ve ridden those roads on 28s (both tubed and tubeless) at about 60psi front and 70psi rear at ~150 lbs. No trouble with flats running tires such as the GP5000/equivalent either. Just keep your eyes peeled for potholes and you’ll be fine!

TLDR: your current bike definitely sounds capable, but if you do want a new bike… Don’t let me stop you! :wink:

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I agree with ZDW1995. Last year I rode the VTGF on my titanium framed road bike with narrowish alloy wheels (23 mm external width) on Vittoria Corsa Control tires (28 front 25 rear). The offroad sections have minimal washboard and are surprisingly smooth for the most part. As said the major issue is keeping your eyes open for potholes. If I did it again I would ride my normal tires (Continental GP 5000s) as I felt I lost more being on the corsa control on the 75% of the course that is paved than I gained on the 25% of the course that is dirt. That said if you want to be safe you don’t need anything more than the corsa control and 25-28 is fine. As for gearing my lowest gear was 34 front 32 rear. I wish i had a 34 rear. I rode all the climbs without walking but MANY were walking Lincoln Gap including folks in front of me and I was in the front 25% of riders so these were legit riders that were walking. I had to paperboy the last few hundred yards to stay on the bike. takes a sustained 275 watts to get over Lincoln (165 pound rider). I was completely redlined for the last 15 minutes or so of that climb. My FTP was about 250 at the time. I don’t think I would of made it with a 28 tooth rear cassette personally. This year sounds like lincoln is the last climb, which makes bailout gearing even more important.

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Yep, as another Vermonter - haven’t done the Gran Fondo but have ridden pretty much the entire route a bunch and I’d agree with everyone else. I wouldn’t worry too much about tires. 30c would be great, 28c’s fine, too.

That said, I’d echo other folks about the gearing, as well. These climbs really are quite steep and your legs will thank you at the start of your third gap if you can get a bigger cassette in there.

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I haven’t ridden the Fondo but I have done all the gaps; the only stretches of road I haven’t done are the dirt roads from Sugarbush to Lincoln Gap Road and from Lincoln to Ripton. I rode a Pinarello Dogma F10 with a 50/34 up front and 11/30 in back and Conti GP5000s at 25 mm. From a gearing perspective, it all depends on your FTP. The course is kind and puts Lincoln as the second gap. I was carrying a 340W FTP (~4.4-4.5 W/kg) at the time and did Lincoln 4th with 70-75 miles in the legs already. I got up just fine without having to swerve or walk. One thing that’s “nice” about the climb is the steepest parts are punctuated with just barely less steep parts.

Tire-wise, I was fine descending Lincoln, though it was a bit hairy at times. I was running 90ish PSI with butyl tubes. I did not flat. Plenty of cyclists ride these gaps every year on whatever road bike they have.

Enjoy the ride!

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@jfranci3 @ZDW1995 @BTTG @FergusYL @The_Conductor Thank you all for your feedback! After a few weeks of silence, I decided to purchase a new Giant TCR with 34:34 ascending gear ratio. It can take 32 mm tubeless tires.

I’m not ditching my old-school-cool titanium bike with mechanical shifting and max 28 mm tires. I’ll hopefully still take it out for longer, less steep, all-pavement stuff… at least that’s what I tell myself.

Now onto tire selection. The new TCR came with 25 mm tires, but I’ll probably put on 28mm or 30mm Conti GP5000 S TR (tubeless hookless).

Which of you are doing the ride this year?

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Awesome! Happy new bike day :smiley:

Can’t go wrong with 28s or 30s, in my opinion.

I won’t be around for the VTGF, but I’ll be at the Green Mountain Stage Race over Labor Day Weekend, which features many of the same roads!

@mattclarke and contributors, thank you for this thread. I’ll be there. As for tires, I just clicked ‘buy’ on GP 5000 S TR 30’s. I’ve been riding Veloflex Corsa Race TLRs which only come in 25s. I’ve had a great experience with those tires, but alas they don’t come wider. They’re fine for the occasional stretch of dirt road, but not what I’d want to be piloting for ~27 miles of dirt roads.

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So, it sure looks like rain! I’ll be running the same tires, Conti GP5k S TRs! Just mounted them two days ago. I’ll be grateful for the 30mm width descending on wet roads! And for traction up Lincoln Gap.

Anyone have any nuggets of wisdom for a rainy day when you get to ride 112 miles w/ 9k feet of clmbing??

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