Author Topic: footpeg vibration  (Read 9477 times)

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pollocka

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on: September 19, 2010, 01:03:44 am
My 2010 C5 military (900 miles now) had a serious vibration in the footpegs starting at 50 mph.  The dealer identified a loose engine mounting bolt, and it's much better now, but the left foot still buzzes as soon as I hit 55. Any suggestions?
Also - the owner's manual says the tire inflation should be 18 front, 28 rear. Is this for real? I've never ridden a tire that low.


gashousegorilla

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Reply #1 on: September 19, 2010, 01:28:29 am
My 2010 C5 military (900 miles now) had a serious vibration in the footpegs starting at 50 mph.  The dealer identified a loose engine mounting bolt, and it's much better now, but the left foot still buzzes as soon as I hit 55. Any suggestions?
Also - the owner's manual says the tire inflation should be 18 front, 28 rear. Is this for real? I've never ridden a tire that low.

 Welcome pollocka . love that C-5 military!  That Buzzing should go away soon , as the engine breaks in. Yes. crazy as it sounds, the tire pressure is correct. I have found the best range of pressure is 18- 22 front, 24 -28 rear.  The lower they are, the better they seem to be, for me, especially on the highway. Thats with the stock avon roadriders.
 Dan.
An thaibhsí atá rattling ag an doras agus tá sé an diabhal sa chathaoir.


r80rt

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Reply #2 on: September 19, 2010, 01:56:21 am
I run 27psi in front, 29 in the rear,18 is too low. The bike will get a lot smoother in a few hundred more miles. Around 1500 to 2000 miles it'll be a different bike,
« Last Edit: September 19, 2010, 01:14:11 pm by r80rt »
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Andy

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Reply #3 on: September 19, 2010, 04:23:04 am
The footpegs on my C5 loosen up quite a bit.  You gotta give 'em a tightening every few hundred miles and the peg buzz goes away. 
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2bikebill

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Reply #4 on: September 19, 2010, 08:34:14 am
18psi on the front is way too low. The recommended pressures for Avon Roadriders are 27 front, 29 rear. I have these tyres at these pressures on my G5 and it handles like a dream.
There are several misprints in the owners manual. For instance they also recommend lubing the chain every 3000 km !!!
Go with the conventional wisdom
« Last Edit: September 19, 2010, 08:37:31 am by WillW »
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gashousegorilla

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Reply #5 on: September 19, 2010, 04:42:50 pm
  I hear ya Will about conventional wisdom, And I was reluctant to run my tires that low. But on the C-5, with these tires it makes a world of difference at high speed.And no sacrifice at the low speed stuff. The G-5 has a different frame set up. Adding a little flex to those low profile tires on the C-5 really helps.
 We did alot of testing after we found the fix on my C-5. Just to get it the best that we could.A little bird whispered in my ear to just try it. Man, night and day ! It got rid of that riding on beach ball effect that i was feeling on the C-5. 18 may be too low for some, but try going down to 22 front 24-25 rear. Try it. Go from there. Do your tires feel or  look flat? Do they feel greasy? These are not heavy bikes, much lighter then most. I think that has alot to do with it. To be honest I would say, along with the correction of the tail section on my C-5, The tire pressure played, an almost as important factor.
 I put 150 miles on my bike yesterday, running 18 - 22. The vast majority of it on country roads, not more then a qtr mile of a straight away. Going anywhere from 35mph to 55mph, ALOT of twisties. My buddy was on a ZRX 1200, and I stayed turn for turn with him ::) ::), He may have been being a little nice. Then blasted home on an interstate, cruising at around 70 mph. I had no problem.
« Last Edit: September 19, 2010, 05:09:03 pm by gashousegorilla »
An thaibhsí atá rattling ag an doras agus tá sé an diabhal sa chathaoir.


pollocka

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Reply #6 on: September 19, 2010, 05:51:01 pm
Thanks for sharing all your experience with me, as I have almost none. The inflation hasn't been causing me any problems, I was just curious about such low numbers, as my husband's bike runs 32/36 solo. BTW,  I LOVE this bike.


2bikebill

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Reply #7 on: September 19, 2010, 06:09:35 pm
I ran on the original tyres (speedmasters) at 18/28 when I first had the bike, then increased the front to 22, which I preferred. When I fitted the Road Riders, it was a revelation - the bike just leaned so naturally into the curves  - I didn't realise how much I'd been having to haul it over before. And no more tracking along dodgy road surfaces!
I've always run these tyres at 27/29 just because that was the manufacturer's recommendation, but interesting to hear your experience of running them lower. I'll experiment a bit when my bike returns re-spragged from the dealer, hopefully soon.
I still don't understand why they put those shite sadomasochismeister tyres on the G5 when they supply the C5 with the Road Riders.  :-\
2009 Royal Enfield Electra (G5)


gashousegorilla

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Reply #8 on: September 19, 2010, 06:25:18 pm
 Yea, I don't know why either?  I bet on the G-5, the pressures your running are probably Good.  The C-5 is a different animal. With a softer, wider profile tyre, I'll bet you could run higher pressures on the C-5? For me It came down to air flow under that very high rear fender, and strong fenderstays. I would notice a bit of tail wag above 70 mph. I believe air gets under the tail, and wags it a bit. Out rigging with my knee's , blocking the air flow would stop it.  That's when we tried the lower pressure, it stopped it, or drastically reduced it. I guess just adding some flex act like a shock absorber?
An thaibhsí atá rattling ag an doras agus tá sé an diabhal sa chathaoir.


2bikebill

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Reply #9 on: September 19, 2010, 06:48:05 pm
Could be. I had the C5 loan bike for a couple of weeks back in april while my G5 was in having the brake shaft replaced, but I was still getting used to being on two wheels after a long (decades!) break, so the finer points I'm afraid were lost on me. It'd be interesting to try one again now just to see - but I'm pretty sure they won't be dropping off a courtesy bike this time when they come for mine tomorrow..... :(
Glad you got that stability problem sorted.
2009 Royal Enfield Electra (G5)


r80rt

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Reply #10 on: September 19, 2010, 08:29:43 pm
I've tried the low pressure from the manual on my C5, that's why I now run 27 and 29. It feels much better to me at that pressure,
« Last Edit: September 19, 2010, 09:46:56 pm by r80rt »
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Kevin Mahoney

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Reply #11 on: September 20, 2010, 03:03:39 am
Conventional wisdom is a good place to start but maybe not in this case. Lets start with the premise that the tyres on the C5 and the G5 are TOTALLY different. One is bias ply, one is radial. One has a very round profile on the tread, one can almost be square (G5 rear). One is designed for a bike about the weight of the G5 while the C5 tyre will support a bike several hundred pounds more than the C5.

You CANNOT compare tyre pressures from one bike to the next with stock tyres in the same conversation.

Lets focus on the C5 since it is the most sensitive to different pressures. The C5 is designed to have very quick neutral steering. Basically if you want to twitch the bar, the bike will twitch - right now. It responds to steering inputs exactly as they are given. The handling of this bike is such that it needs the riders attention all the time. Now for most riders (even low time riders) this is not a big deal and feels natural. You may ride the bike and not notice any of this. The Italian company that tweaked the frame and steering are the same people who design frames for Ducati and most other Italian sport bikes. They offered Enfield three handing options. Slower handling, quicker handling and  all our performance handling. We chose the middle as the other two missed the mark for what we wanted. Frames and suspension were tweaked and the tweaks verified by professional riders on the companies track and the roads around Bologna Italy.

The G5 is designed as a commuter bike. It does not require the same inputs as the C5. It also responds to inputs but in a slower fashion,

The tyres on the C5 are designed to have a wide radius of surface area to contact the road. This allows for fairly radical riding angles. As a practical matter you will be scraping the tool boxes before you run out of tyre.  For us the most important thing is how much surface of the tyre is in contact with the road. Higher pressure less contact patch, low pressure more contact. There are many factors that go into pressure recommendations but the they revolve around weight and handling characteristic's.

We had a customer show up at a dealers with what he described and an ill handling bike. It was squirrelly by his report. The dealer rode the bike making no adjustments and agreed with the customer.. When asked about air pressure the customer said that he had them filled up to the pressure stated on the side of the tyre. If you look at the C5 tyres. It says what the maximum load carrying capability of the tyre is at a max. inflation pressure – In the case of C5 tyres about 40 PSI.  None of this information is at all relevant to what the tyre pressure should be. In the  of the C5 the 40 lbs pressure is grossly too high. At this pressure and at the weight of the C5 he probably had a tread patch as thin as a piece of pencil lead and the bike no doubt would squirrel around.  This bike was completely cured just by inflating the tyres correctly.

How do you find the correct pressure? You will find a published tyre pressure in the owners manual and on a plate/sticker attached to the down tube. In theory they should be the same. I think in the case of the C5 they are but I am writing from a hospital bed and cannot say for sure.  The most accurate way to inflate the tyres is to use the number stamped into the plate mentioned above. It is put there by the designers and is not subject to misprints, non current data etc.

This has been interesting for us since with Bullets of all models including the G5 tyre pressure didn't change the handling characteristic's that much given the nature of the tyres, frame and suspension.  I have almost never had to talk about this until the C5 came out. I also never realized how few people actually read their owners manuals.
To give credit where credit is due I have learned almost all of this from Scooter Bob and am parroting his advice from our conversations and experiments.

Best Regards,
Kevin Mahoney
www.cyclesidecar.com


gashousegorilla

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Reply #12 on: September 20, 2010, 03:56:41 am

To give credit where credit is due I have learned almost all of this from Scooter Bob and am parroting his advice from our conversations and experiments.


Kevin, 1000 % scooterbob. Of course that little bird in my ear was infact our resident Guru. And I am very happy that you mentioned him. My not mentioning him was only out of a deep respect for his humility, believe it or not ;)  He spent countless Days with me on this, nights, weekends etc. And I do believe he enjoyed every minute of it. Almost as much as I did. Aways constructive, positive and open minded. I have never met anyone who loves what he does as much as he does. Countless Pm's and emails. At times I thought, Man, let me give him a break .Then Bang, at 10 pm on a sunday night, while I was in the garage, I'd get  Pm from him,asking about this or that. The man is always thinking about Bikes.
 Now I don't mean to get him in trouble, and get everone thinking, that's the kind of service everyone is gonna get. But I think you can agree, my problem was not the run of the mill type. To use his word's, "the tip of my tongue has been turning blue". An unbelievable Guy  and someone I consider a friend.  ;)
 Dan
An thaibhsí atá rattling ag an doras agus tá sé an diabhal sa chathaoir.


Roger

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Reply #13 on: September 20, 2010, 04:29:46 am
How does the 19 inch wheel kit change this conversation?  Same tire pressure?
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gashousegorilla

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Reply #14 on: September 20, 2010, 05:05:48 am
How does the 19 inch wheel kit change this conversation?  Same tire pressure?
That's a good question Rodger. I guess it would depend on what tire you use on the front. In my case I don't think it changes the effects of the pressure that much. I am using the same Avon roadrider, Same with and sidewall size. 90/90/19. It is 1" taller, but the contact patch and sidewall are the same.
An thaibhsí atá rattling ag an doras agus tá sé an diabhal sa chathaoir.