[Manatoc fox]

Just bought and rode my brand new C5 military last night, and everyone on this forum was right!  It is amazing and I can feel the early set in of Perma-grin already.  However, I'm a little concerned.  The break in procedure calls to keep the bike under 40 for the first 300 miles.  Is this what the speedometer reads or how fast it feels like I'm going, because at 35 it feels like I'm about to do a land speed record and I would hate for the bike to think it was going too fast, get scared, and throw a rod or something  (bikes are tricky creatures I hear).  Anyone studied this phenomenon yet?

[High On Octane]

How long have you been riding?  Is this your first bike?  I really highly doubt that the speedo is so off that you're going much faster than 40mph at an indicated 35.

Scottie J

[Manatoc fox]

Sorry, I was making a joke.  I've read before how going 50 on this bike feels like you're doing the ton.  I didn't believe it until I rode it.  Now I'm a believer, as they say.  Just very excited about the brand new Thumper!  It's an absolute blast to ride.

[High On Octane]

I guess being a performance junky I always feel like I'm going too slow.

[bob bezin]

a lot of these speedometeres are 5 to 7 miles optomistic.

[Gypsyjon]

I went thru one of those neighborhood radar things. My speedo said 40 mph, radar said 35 mph.

[redcat]

My 2002 is about 6 MPH over

[olhogrider]

Glad you are enjoying your new ride! Most speedos read high. I heard it has to do with massive EU fines if they read low. I think they didn't change the drive when the C5 got the 19" front. Mine is exactly correct. Checked by GPS and radar.

[bob bezin]

what gear is that 35mph  ?in in 5th it might be lugging.

[GSS]

Glad you are enjoying your new ride! Most speedos read high. I heard it has to do with massive EU fines if they read low. I think they didn't change the drive when the C5 got the 19" front. Mine is exactly correct. Checked by GPS and radar.

Yes. My C5 with a 19" wheel and 3.5x19 Dunlop K70 is spot on as well!  It used to be off by +5 mph with the wobbly OEM 18" wheel.

GSS

[Arizoni]

My G5's speedometer is also very close to being correct.

Just yesterday I rode past one of those radar units that has a big numerical readout to tell drivers how fast they are going.
Usually when I pass it, some other car is close to me so it picks up their reflection but this time, I was all alone.  It still had trouble seeing my reflection and it changed its mind several times about my speed as I approached it.
When I got about 50 yards away it finally got my speed and showed it to be within 2 mph of what my speedometer said I was at.

I think the real problem is the speedometer drive was made for 19" wheels and RE uses the same speedometer and drive on the 18" wheels.
Being smaller, they turn faster so the speedometer shows the faster speed.

Mathametically, the difference between a 18 and 19 inch wheel is 1.06.  That's 6 percent faster for the 18 inch wheel which shows up as being about 53 mph if the motorcycle is actually going 50.

[Adrian II]

The British factories used speedo gearboxes with ratios of 19:10 and 21:10 as well as 2:1 and 1.25:1, probably at the same time as they started using 18" rear wheels. I think the Indian RE stuff is all 2:1.

A.