mokwepa Posted October 23, 2013 Report Share Posted October 23, 2013 I am still amazed by the amount of bike enthusiasts that get this wrong......even bike dealers, importers etc etc. FACT: SMALLER FRONT SPROCKET: bike will have more power/acceleration low down and less top speed. Gears will feel shorter as revs will climb quicker. LARGER FRONT SPROCKET: Bike will accelerate slower but will have a higher top speed. Gears will be longer as revs take more time to pick up. SMALLER REAR SPROCKET: bike will have more top speed but will accelerate slower. LARGER REAR SPROCKET: bike will loose top end speed but will gain acceleration. Please argue with me on this.........! It amazes me that there are some pretty clued up guys out there that will baffel your mind with technical data but still skrew up gearing. Quote Link to comment Share on other sites More sharing options...
mokwepa Posted October 23, 2013 Author Report Share Posted October 23, 2013 Oh yes and before someone tries to get smart......with trials bikes, less acceleration is considered taming a bike down, not less top speed. Sorry if I come accross abrupt and blunt but this is a FACT that seems to confuse allot of new guys that costs them money and steers them in the wrong direction. Quote Link to comment Share on other sites More sharing options...
zerorev3rev4 Posted October 23, 2013 Report Share Posted October 23, 2013 thought it was funny when a young n 21 whose had motorbikes and push bikes thought a mountain bike with 3 front cogs and 7 rear had 10 gears , but then on the other hand not many folk can tell a bolt from a nut Quote Link to comment Share on other sites More sharing options...
dadof2 Posted October 23, 2013 Report Share Posted October 23, 2013 Unfortunately #1 is not correct. Fitting a large gearbox sprocket or smaller rear wheel sprocket may not increase top speed, in many cases it will do the opposite. What it actually does is lower RPM at the maximum speed the bike will reach. Quote Link to comment Share on other sites More sharing options...
mokwepa Posted October 23, 2013 Author Report Share Posted October 23, 2013 Now that makes no sense at all. #1 was a small up front....which will increase acceleration and drop top speed. Ever watch land speed records? Thats why the bikes, cars etc cannot pull off from a stands till, they need a push to help them get going because their gearing (in trials bikes - sprockets - we not talking about internal gearing) is set up for maximum top speed which sacrifices acceleration. This is a no brainer if physics is understood. Quote Link to comment Share on other sites More sharing options...
b40rt Posted October 23, 2013 Report Share Posted October 23, 2013 thought it was funny when a young n 21 whose had motorbikes and push bikes thought a mountain bike with 3 front cogs and 7 rear had 10 gears , but then on the other hand not many folk can tell a bolt from a nut He's probably right, if you have any mechanical sympathy. 1 Quote Link to comment Share on other sites More sharing options...
rob214 Posted October 23, 2013 Report Share Posted October 23, 2013 i never really understood physics, that's why i spend so much time falling down. but i rearly love listening to guys talk about gearing(not) one guy says he's gearing up his bike and the other says he's gearing down his bike.......... oh well rob Quote Link to comment Share on other sites More sharing options...
mokwepa Posted October 23, 2013 Author Report Share Posted October 23, 2013 I hear you rob but I get annoyed when people who I trust and turn to, give me wrong advice. Im gonna sit back and enjoy the show Quote Link to comment Share on other sites More sharing options...
grib Posted October 23, 2013 Report Share Posted October 23, 2013 Oh yes and before someone tries to get smart......with trials bikes, less acceleration is considered taming a bike down, not less top speed. I don't think i have ever heard of someone fitting a larger front sprocket or smaller rear to tame a bike down. Quote Link to comment Share on other sites More sharing options...
lineaway Posted October 23, 2013 Report Share Posted October 23, 2013 Well Mokwepa, I`ve had more Beta`s than any brand. I usually went lower on the front. Not for more acceleration in first, but a more useable 2nd. ( It does always bring top speed lower, but awesome 5th gear wheelies.) I`ve bought several left over world round bikes, always a little strange on gearing and always lower. (slower) But not for a lower first. Quote Link to comment Share on other sites More sharing options...
mokwepa Posted October 24, 2013 Author Report Share Posted October 24, 2013 Well Mokwepa, I`ve had more Beta`s than any brand. I usually went lower on the front. Not for more acceleration in first, but a more useable 2nd. ( It does always bring top speed lower, but awesome 5th gear wheelies.) I`ve bought several left over world round bikes, always a little strange on gearing and always lower. (slower) But not for a lower first. That makes perfect sense. 1st gear on trials bikes is often too short as revs climb too fast but will not give you enough speed for bigger moves, move up to second and and you get a nicer balance of acceleration with a touch more speed. If you compare the front/back sprocket ratio between a trials bike vs a enduro, mx, gp track bike......the trials bike will always have a smaller front to back sprocket as trials bikes need aggresive acceleration in almost all gears. Take almost any other bike and try pull away in 3rd or 4th gear.....it will have almost no grunt on pull off.....but when they get going, then you get the speed. Quote Link to comment Share on other sites More sharing options...
copemech Posted October 24, 2013 Report Share Posted October 24, 2013 Gearing is simply a function of torque multiplication. It will not give the motor more power or more speed than the motor will overcome the resistance of (drag) at high speed. Three basic ratios to consider and only two you can change! Primary- crank to trans input Trans- may vary from say 4:! to overdrive at 1:1.2 I would guess. Final- (chain on a bike) somewhere around 4:1(40T:10T) Then going to say 48T/10T on the rear would give you a 4.8:1 ratio so a torque multi increase of 0.8 yet effectively narrowing the intermediate ratios of the trans and making other selections more usable in some ways. Doing all that math in a section really makes my head hurt, so I just use the clutch and throttle or go up a gear if I don't like the other one! Ha! Quote Link to comment Share on other sites More sharing options...
mokwepa Posted October 24, 2013 Author Report Share Posted October 24, 2013 No idea what you just said English ? Quote Link to comment Share on other sites More sharing options...
billyt Posted October 24, 2013 Report Share Posted October 24, 2013 Riders dont gear down on the front to lower first gear they usually gear down to make second gear more usable i.e. lower. They then use first gear as a grannie gear and second as a general riding gear. There are sections where torque is needed and sections where speed is needed. I think that you are correctly mathematically/physics but wrong in practicality. Trials riders when changing front sprockets 99 out of a 100 times will put a lower front sprocket on. You can throw all the math you want at us it does not change the fact that we put smaller front sprockets on our bikes. Quote Link to comment Share on other sites More sharing options...
steveo Posted October 24, 2013 Report Share Posted October 24, 2013 Riders dont gear down on the front to lower first gear they usually gear down to make second gear more usable i.e. lower. They then use first gear as a grannie gear and second as a general riding gear. There are sections where torque is needed and sections where speed is needed. I think that you are correctly mathematically/physics but wrong in practicality. Trials riders when changing front sprockets 99 out of a 100 times will put a lower front sprocket on. You can throw all the math you want at us it does not change the fact that we put smaller front sprockets on our bikes. .Great answer Billy, Some find the gearing down of the front by one tooth will not only slow the bike so they can creep along slower in first gear, using it in first gear and maybe over reving it will still get you there and when you back off it slows you much quicker , giving you more time for the next bit of section you are to negotiate. Quote Link to comment Share on other sites More sharing options...
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