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  1. #1
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    Tires Pros and Cons

    We've used Continental Gatorskins 700x28s but would like to know the pros and cons in swtiching to 700x25s (same brand). The team weight is about 290 lbs. and we have an aluminum tandem and ride primarily on paved roads in Illinois.

    Thanks for the help.

    LB

  2. #2
    hors category TandemGeek's Avatar
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    Neglible differences depending on psi.

    For example, if you ran the 25's at a higher psi and have smooth roads you'd probably find the ride performance to be a bit more aggressive with increased road feedback and perhaps, even find that the bike feels like it's a bit more responsive. The latter probably has more to do with reduced rolling weight, smaller aerodynamic footprint, and the livelier feel.

    Down side is, the larger tire provides a bit more suspension for the stoker and they, more so than you, might find the ride on a higher psi 25 to be a bit more harsh IF she's not using a shockpost and your roads aren't super smooth. Having lived in the Chicago suburbs back in the 70's I don't recall that our roads were all that smooth... lots of concrete roads with expansion joints and patchwork asphalt.

    An easy way to experiment would be to move your 28 from the front wheel to the rear wheel next time your rear tire wears out and fit a new 25 to your front wheel. If you're happy with how the bike handles, that may be your answer. You can always move it to the back when the 28 wears out and see how your stoker likes it. If she is adverse to the 25, just replace it with another 28 and stash your 25 for re-use on the front when it starts to get a bit long in the tooth OR carry it as a spare.

  3. #3
    Banned wagathon's Avatar
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    Quote Originally Posted by LuisB
    We've used Continental Gatorskins 700x28s but would like to know the pros and cons in swtiching to 700x25s (same brand). The team weight is about 290 lbs. and we have an aluminum tandem and ride primarily on paved roads in Illinois.

    Thanks for the help.

    LB
    Interesting question as I have a pair of 28-Gatorskins that I was planning to put on a bike that I sold. Do you have any feedback about your 28s? I have some high pressure 25s on the bike that I now have and was thinking of putting on the 28s Gatorskins on it.

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    We've used Panaracer 30s before switching to the Continental 28s. I thought we went faster on the 28s maybe not so much that they're narrower but because they were just better tires overall compared to the Panaracer 30s. Did not experienced any flats for about 1,000 miles riding on mostly paved roads. I really like the Gatorskins but the LBS only carry them in the 25s. If comfort for the stoker is the main issue, I will give them a try since we use a suspension post in the rear.

    LB

  5. #5
    Banned. galen_52657's Avatar
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    I don't have a lot of experience with different sizes and brands. However, when I bought my tandem, Larry Black, the owner of Mt. Airy Bikes said ditch the stock tires and use Conti 28's. I have the Ultra 3000 wire beads which can be had for under $20 each:

    http://www.nashbar.com/profile.cfm?c...eid=&pagename=

    They will take 125 PSI.

    edit: I see the link is for the kevlar bead...even better! Our team weight is around 360 lbs.

  6. #6
    K&M
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    We are also about a 290 pound team. We've used mostly Conti Gatorskin 28s on the tandems we've ridden and liked them fine -- no problems. Our new Burley came with Pasela 28s and they were also fine, although maybe not as long wearing as the Gatorskins. I am thinking of putting on some Michelin axial or pro race 25s for the Davis Double this weekend, just to give us a little better performance and feel for the road. If it seems to make enough difference, I am thinking it might be worth running high-end 25s or even 23s in longer or more competitive events, then switching back to the long wearing Conti 28s for training and riding around town.

    Any thoughts from the experts?

  7. #7
    hors category TandemGeek's Avatar
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    There was a CAT3 on our local team "back in the day" who did all of his training rides on a beat-up Trek 2200 or something like that who carried a 28 oz water bottle filled with pennies. On race days he pulled out his Trek OCLV and left the waterbottle with the pennies at home. It worked for him...

    So, the moral of the story is, what ever works best for you.

    Give it a go and if you and your stoker don't find yourselves biases towards the ride characteristics of one tire vs. the other, then it could be a good move. FWIW, I was never able to adjust to the "feel" of a 28mm or larger tire on our first tandem and have used 23mm or 25mm Vredestein Fortezza's exclusively ever since: 23's for smooth roads near to home and 25's for chip-seal or unknown conditions associated with travel. Of course, we don't race so that makes our requirements horses of different colors.

    The performance tires don't last all that long; about 2,400 miles/ea when rotated front to back or 1,200mi for a new tire on the rear. However, I've been able to find them on sale for ~$25/ea. now and again and stock-up. I think I've got three 23's left and perhaps four 25's (special order @ $36/ea with club discount) in my tire bin.

  8. #8
    K&M
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    What kind of pressure do you run in your 25s and 23s? The Rolf folks say never to put in more than 120 lbs. when using their high-zoot tandem wheels, regardless of what kind of tire you're running. And what about the size of the rim? I understand from posts on other threads that some tandem rims are too wide for 23s. I hope this isn't a problem with the Rolfs.

  9. #9
    hors category TandemGeek's Avatar
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    Quote Originally Posted by K&M
    What kind of pressure do you run in your 25s and 23s? The Rolf folks say never to put in more than 120 lbs. when using their high-zoot tandem wheels, regardless of what kind of tire you're running. And what about the size of the rim? I understand from posts on other threads that some tandem rims are too wide for 23s. I hope this isn't a problem with the Rolfs.
    Rolf wheels... that's a new data point in this discussion and, yes, Rolf does specify a 120 psi limit as well as a maximum tire width of 28mm for their rims. Of course, they also incorrectly state that drum and disc brakes installed on tandems are only to be used as drag brakes to supplement the rim brakes; oops.

    To your questions:

    700x23 Vredestein Fortezzas are normally run at 140 - 145 psi.
    700x25 Vredestein Fortezzas are normally run at 130 - 135 psi, but dropped down to 115 - 120psi when road conditions demand a more compliant tire, e.g., chip-seal in Texas, Virginia, etc...

    As for rims, we use 700c Velocity Deep-Vs which, according to Velocity, will handle any psi currently offered by tire manufacturers. We have used the Velocity rims exclusively on both road tandems since '02 -- perhaps 10k miles or so -- with no issues or even any hints of a weakness and have ridden away from some fairly nasty pothole encounters at 25mph with only dented rims (Note: pacelines are dangerous when the lead riders don't call out obstacles & hazards).

    The key to figuring out if a given rim is acceptable for use with a given tire is the inside bead seat diameter, not the overall rim width. For example, our Deep-V's have an outside rim width of 19mm and an inside bead width of 14mm; ideal for our 23's and 25's but near the margins for a 28. Velocity's Dyad rims -- sold as OEM on some Co-Motion tandems -- have an inside bead width of 18mm which is marginal for a 25mm tire; however, I've seen a bunch of tandems with Dyads running 25mm tires over the years so 18mm "seems" to be about the upper limit 25's; 23's would be a stretch.

    A good nominal inside rim width compatibilty table can be found at Sheldon Brown's Website: http://www.sheldonbrown.com/tire_sizing.html#width

    Of course, tire sizing is sometimes an inexact science, e.g., Continental's tires have tended to run small and earlier models of the Vredestein's seemed to run big. Anyway, you get the idea; it's always a good idea to search out the inside bead width of rims before buying to make sure they are suitable for any of the tires you plan to run.

  10. #10
    K&M
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    I've never been much of a fan of high tire pressure. It seems like any gains due to reduced rolling resistance are more than lost when your rock hard tire loses traction on gravel or under hard acceleration. I usually run my tires on my single bike at around 100psi and have never felt like I was at a competitive disadvantage. On the tandem, I've been running the 28s at about 120psi in the rear and 110psi in the front. I'm wondering if with smaller tires it will really be necessary to go above 120psi to avoid pinch flats?

  11. #11
    hors category TandemGeek's Avatar
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    Quote Originally Posted by K&M
    I've never been much of a fan of high tire pressure. It seems like any gains due to reduced rolling resistance are more than lost when your rock hard tire loses traction on gravel or under hard acceleration. I usually run my tires on my single bike at around 100psi and have never felt like I was at a competitive disadvantage. On the tandem, I've been running the 28s at about 120psi in the rear and 110psi in the front. I'm wondering if with smaller tires it will really be necessary to go above 120psi to avoid pinch flats?
    I wasn't either, but those are Vredestein's spec psi recommendations and, for whatever reason, the Vred's don't seem to suffer the usual effects of rock-hard tires; very reminiscent of tubulars. Regardless, everyone just needs to figure out what works best for their personal preferences, local conditions, etc... to find the right balance between road feel, traction, comfort, and reliability.

    As for avoiding pinch flats with narrow tires & the Rolfs or any other psi restricted rims, I would expect that you'd have no more problems with 25's at 110/120 than the 28's at 110/120. However, 23's would probably be a different story. Again, the best answer will come with personal experience and experimentation on your local roads.

    Anecdotal Entry: When we toured the California coast in '02 we used our 25's with perhaps 120 - 125 psi on most days. No problems and no flats during the entire two week tour. I wish that had been the case for some of our fellow teams, all of whom were running larger tires. Of course, for one couple it was bad tubes that were at fault for three flats and for another it was the wire bead coming apart that led to the blow-out.
    Last edited by TandemGeek; 05-18-05 at 06:06 PM.

  12. #12
    K&M
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    Got some Michelin Pro Race 25s, but when I took them out of the box I noticed they appear to be a different animal than the Pro Race 23s I am used to (different tread compound, etc.). They also have a VERY low Max. PSI (102!). As a consequence, we went ahead and did the Davis Double this weekend on our tried and true Conti Gatorskin 28s. Now I hear that a tandem guru at a very well respected LBS says the Pro Race 25s are great tandem tires, that the stated max is way below what they are actually designed to handle, and that putting 115-120 psi in these tires is no problem.

    Any thoughts?

  13. #13
    K&M
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    Latest tire experiment:

    Put a pair of bright yellow Conti Grand Prix 3000 25s on the tandem. Very flashy. The color went well with the Rolf wheels ..... but after only 276 miles (albeit over some very rough roads) the rear tire is worn down to the threads all the way around!

    Yikes! I guess I'll have to locate some of those Vredestein Fortezzas.

  14. #14
    hors category TandemGeek's Avatar
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    Quote Originally Posted by K&M
    but after only 276 miles (albeit over some very rough roads) the rear tire is worn down to the threads all the way around!
    276 miles? Good grief!

    If you do opt for the Fortezza's make sure they're not the Tri-Comps.
    Here's one source that's not to obscenely expensive that offers both the 700x23 and 700x25. If you have less than perfect roads opt for the larger diameter. http://www.biketiresdirect.com/htmlpages/VRFOR.htm

  15. #15
    Senior Member zonatandem's Avatar
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    In our 30+ years of tandeming, we have run the gamut of tire brands and sizes.
    Diffferent batches of the same tire brands don't always behave the same +
    road/riding conditions can vary greatly.
    Currently we favor Maxxis Detonators (no, have NOT exploded one!) and Michelin Pros.
    For stoker comfort, it may be nice to run one-size wider tire for her than on the front, as stoker absorbs most of the road shock/vibrations.
    Experiment around a bit, and by the time you find your 'best ever' tire, they'll discontinue making it!

  16. #16
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    My rims have an 18.5 mm inside bead. I assume from TandemGeek's link I should only use 28 or larger tires. Does anyone know whether I can use ultralight tubes that are rated for tires between 18-26? Does 2 mm make much of a difference?

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