21" Front on an '07 GSA - on road handling

Discussion in 'GS Boxers' started by mtmc, Jun 27, 2010.

  1. mtmc

    mtmc Adventurer

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    I am looking into a 21" front wheel for my '07 GSA. I would like some plain speak input on how it will affect the on road handling on the bike. I have read and read on here and elsewhere, terms like "squirrelly" or "slower out of the corners" are great but, may paint a different picture depending on where one is from.

    Please limit responses to on road (tarmac to cobblestone, straight and flat to switchback ascents and descents) attributes. I know where to get the wheel, what mods do and do not need to be made, and how much they make a difference in the dirt. Thanks in advance guys.

    -MTMc:ear
    #1
  2. Kiwirich

    Kiwirich Been here awhile Supporter

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    The truth is that it all depends on what you expect from it.
    The 19" has a 110 tyre & the 21" has a 90 tyre. There is less rubber deformed to the road surface to stick to it. I've noticed that when you start getting right over to the edge of the tyre that it starts feeling less "planted,squiriley"
    or some other highly non-technical term...........than the 19" felt.

    When I don't ride with such vigor, It feels absolutely fine.The 21" feels like it has more rotational mass. Like putting TKCs on after using Anakees.

    I decided to stop worrying & just ride it.

    Regards
    Richard
    #2
  3. woody's wheel works

    woody's wheel works Built to Last

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    in replying to your rather specific question ,,,,the one variable that will affect the answer is the tires/tire style that you will be using ,,,they have a a wide range of response handling characteristics depending on their style and bias for either riding mainly off -road or On-road....so i think that the feedback should include

    1,,the tire model
    2,, the model bike
    3,, the air-pressure in PSI
    4,,type load carried and where[on the bike as opposed to where to:wink:]
    5,,pavement conditions [wet/dry/asphalt/concrete]
    6,,type of road
    7,,rim-width [generally IMHO the 1.6/1.85/2.15x21rims share a generic propensity the narrower,, the better in the dirt and conversely the wider ,,the better in the pavement/twisties]

    FYI,,,the list below covers most of the spectrum of what's available, in the dual-sport spectrum,,,,,there are many street only 21'' tires that work even better than what's below if it is street only riding you do,,

    FYI,,,on my '06 R1200GS a generic response that seemed to apply to just a 21'' wheel in general,,relative high tire pressure circa 38-44psi tended to have the bike weave a little more at over 100mph,,,36 PSI settled it down some,,there is a slight difference in feeling planted doing the usual 80 cruising speed,,,, when attacking the switch-backs the front end felt like it wants to walk away UNTIL

    uNTIL i had the good fortune to be introduced to Laine Mac Tague's Earth Rider riding school by my old road-racing buddy and canyon crazy Neil Reynolds.

    http://earthrider-amgi.blogspot.com/

    my good fortune came in the form of being allowed to tag along one Saturday a year ago,,,the days course focused exclusively on COUNTER-STEERING....
    folks as fast as ican go road race style on that genre of machinery,,i couldn't hoard the big beemer through the twisties on the 21''s UNTIL...yes until i unlearned all my hanging off knees out stuff and started to counter-steer,,,i thought i found the Holy Grail,,,,and now provide that insight and free lessons to anyone trying a 21'' wheel...what a difference a day at Laines school made:thumb,,,thank you Laine and thank you Neil:beer

    just had to toss that into the basket of available,,because at days end i was cruising the twisties without breaking into a sweat on Dunlops street legal Paris -Dakar 908 RR knobbies.
    .....so this technique alone erased the riding impressions i had before on the various tires listed below:


    FYI,,there are quite a few tires available going from street only to every shade in between to mainly dirt use...

    FYI<< a brief list,,listed as %street/%dirt

    Dunlop
    DOT D606 real off road performance/aggresive dirt
    D908RR rally racer/paris -dakar

    Continental
    TKC-80 tubeless
    Twinduro 40/60
    Conti Escape 70/30

    Metzler

    Enduro 3 Sahara tubeless
    Karoo tubeless 80/20
    MCE Karoo 2 90/10 tubeless
    Tourance 90/10

    Michelin

    Baja x-country race/adventure tire

    Bridgestone
    Enduro 20/80
    Trail wings 80/20

    Pirelli

    Scorpion 20/80
    MT-21 90/10
    MT-90-A/T 70/30
    MT 60-R 60/40
    MT 90 S/T 95/5 performance touring

    Avon

    AM24 Gripster 50/50
    AM43 Distanzia 90/10

    :super
    woody
    #3
  4. chilango

    chilango super-user

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    The only difference I could find was a tiny bit of wobble when overtaking a car doing 95ish on the interstate.
    My set up is a 21 inch front from an HP2 that the gentleman above GS'd for me. Conti's TKC80 were also installed by Woody (perfect balancing...)
    The wobble was experienced with a pillion, and three cases, fairly loaded. I run by psi at 40.
    (thanks again Woody for my wheels, I have done dirt in PA, and just came back from a weekend in VT) Mountain pass roads are bliss.
    #4
  5. mtmc

    mtmc Adventurer

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    Thanks, Woody, I was hoping you might get involved, glad you got in early.

    The run down - my bike is currently in Portugal in storage. Go to Europe at least two months a year to ride, moving into Spain on the next trip and continuing at a tourist's pace through Europe, Asia, and maybe Africa until bureaucratic red-tape or geo-political unrest become unreasonable or I need a boat to go any farther. No set routes just meandering down any road that strikes my fancy, tarmac or not. Not seeking out dirt but, not avoiding it either and, avoiding highways as much as possible. Rain or shine. I do not ride like I'm on a race track, I am perfectly willing to go as slow as needed to stay in my lane, on the road, and upright.

    1. Tire model - currently Tourances have had TKC's and will change based on changes in a particular countries infrastructure and, willing to try others brands models terrain dependent - I would like apples to apples comparisons - TKC's 19" to TKC's 21" or a 50/50 (such as tourances) 19" to same tire 21"
    2. Bike model - '07 GS Adv.
    3. Psi - run at 42 psi (because it is the tire manufacturer's recommendation) on the road and drop it down 5 psi or or more if I know I'll be off road/rough dirt road for a while
    4. Load fully loaded with a pillion
    5. pavement conditions - wet, dry, asphalt, cobble stones of all types wet and dry in towns with very tight turns
    6. type of road - pick one
    7. rim width - open to suggestions - twisties can be 13% grade up and down with switchbacks (not hairpins) and tight, tight turns in small villages.

    I hope this paints a better picture Woody.

    -MTMc
    #5
  6. woody's wheel works

    woody's wheel works Built to Last

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    for starters,,,i have no intention of running this thread or making final decisions for you all,,i just tossed in some parameters that need to be considered when comparing things,,,
    secondly i get the feeling your questions are not what mtmc had in mind,,,he wanted your feedback on what you've learned running a 21 wheel on the street in a variety of conditions...

    the other business has to do with sharing my favorite tires,,, FYI,my experience tells me they are a rather subjective measure,,BWOE TKC-80s is a great example most guys agree they like the handling but not the price or the longevity,,,some could care less about longevity and/or $$$ as long as they stick

    i would like to honor the thread starter's request ...this would probably e better in the ''Ask woody about your wheels'' thread
    http://www.advrider.com/forums/showthread.php?t=145899

    for right now i'll answer with a few quick observations in bold



    ,
    #6
  7. woody's wheel works

    woody's wheel works Built to Last

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    Jackazz,,,,,are ya satisfied with your wheels even though ya never bought one[from us]:ear:ear:ear


    I did buy it, just used. I love the wheel, I just returned from a 1000 mile trip of
    dirt and backroads and the wheel is awesome! It amazes me what these bikes will do with the 21" front and knobbie tires.
    #7
  8. Jackazz

    Jackazz Been here awhile

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    On that trip we found a lot of single lane pavement on the Oregon part and I had as much fun on that with a 21" front and knob's front and rear as I did in the dirt. I could feel the rear slide a little in some corners but the front was always planted.
    If you ride much dirt get the 21" and enjoy the benefits in the dirt. You'll quickly get used to whatever "feel" it gives on the street in no time and have a great go anywhere bike.
    #8
  9. M@gneto

    M@gneto Moto Itinerant

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    Is the 21" wheel an easy swap? What about the front fender? A 21" front wheel would put the tire 1" closer to the fender, right? Add a knobby and it looks like it would be very close to touching.
    #9
  10. mtmc

    mtmc Adventurer

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    Jackazz - Thank's, man that is the kind of input I was looking for. I appreciate it.

    Mag - Dude, there is a ton of info on that on here and elsewhere.
    #10
  11. M@gneto

    M@gneto Moto Itinerant

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    Sorry guys, I'm new here and still trying to find my way around. There is so much information on here, I figured I'd just hang out in the "Oilhead" forum for a while. I'll look around, I'm sure I'll run across it somewhere.
    #11
  12. MANXMAN

    MANXMAN Overlander

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    This is a picture of GalacticGS's bike with what I believe is a stock fender with the 21" front wheel. If you PM him, I'm sure he would tell you if he is having any troubles with the close fit.

    [​IMG]



    If that is too close for you, this is a fork clamp made by Wunderlich that is designed to give more clearance and they also supply a fender to fit the clamp. This clamp and fender are expensive though.
    [​IMG]




    A picture of the Wunderlich clamp and fender mounted and you can see there is much more space between the fender and the tire.
    [​IMG]

    Hope this helps.
    #12
  13. woody's wheel works

    woody's wheel works Built to Last

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    as soon as i return from my commitments/tech talks at the Osh Kosh Fly-in this week,,i will attempt to wrap up designing the new front fender,,without changing anything else on the bike,,,

    although the wunderlich solution works,,,it does so at quite a$$$$ hit to the pocket-book,,,by moving the lower clamp up the fork tubes, they needed the stronger billet clamps to handle the increased loads placed upon it...

    i have several ideas on doing this ,,i always welcome any of your suggestions....

    in the meantime i have listened to all the riders that have one of my 21's,,the consensus basically is this:

    FYI
    1..there's no problem any where in dry or wet weather on any surface that doesn't have mud build-up
    2,,removing the fender and taking the the 4 screws and re-installing them,
    works fine in muddy conditions,,,makes it easier to re-install the fender later[ya don't have to clean the threads] and on the highway ya do get hit with a fine mist,,,some riders have just stuffed a towel between tank and steering head,,me included

    i'll add any other temporary solutions,,,including an inmates fender adaptation that mounted above the lower clamp

    enjoy
    woody
    #13
  14. M@gneto

    M@gneto Moto Itinerant

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    Yeah, that helps a lot. Thanks.
    #14