[Bmadd34]

Okay, I know this has probably been discussed a multitude of times. However, without a definitive answer given. what are the advantages and disadvantages of the 19 tooth front sprocket on the C5? Or going up one tooth on the drive sprockets? I would rather not get answers that include "Probably", "Might", "Theory", "Supposedly", "maybe", "Could" etc.. I would like to hear actual experiences from those that have made the change. Real numbers. Real results. I am considering installing the 19 tooth sprocket on my C5 in preparation for the ride to Florida. Hitchcocks isn't willing to sponsor my ride with one, so before I spend my money, I want to be sure it will be an asset. Thanks.

[Jako]

With a stock engine I wouldn't recommend changing gearing ratio's ,  I actually lost some top speed in 5th gear when I went up a tooth on my B5.   The stock engine doesn't have enough power to take advantage of the extra gearing. You might mistake the  lower revs at cruising speed as a happier engine but its really just overloaded and struggling to reach its potential. More gearing needs more HP .  Anyway if you were to change the gearing In my opinion the better option  would be the  larger diameter Dunlop K70  tires.

[Rattlebattle]

The trouble with this issue is that you’ll get opposing views....I have a C5 (not a B5), they are different in wheel sizes and standard sprocket size ( or they were; not sure about Euro IV models). I made the change and I wouldn’t go back. Key points: 1. I am not heavy. 2. I never ride with a pillion. 3. My engine is not stock - like many I have free-flowing exhaust and air filter, though in my case compensated via a carb rather than PCV or similar. 4. I don’t live in a hilly or mountainous area. 5. I prefer to use the gearbox rather than just put it in top and boo along. What I am saying is that there is no one-size-fits all solution; the accurate answer is “it depends...”. Personally the largest ie 20 tooth one would be too big for my bike; for me the 19 tooth one is ideal.

[2bikebill]

The easiest kindness you can do to the standard Enfield is change the stock silencer for a less restrictive one. You'll notice a slight performance increase. It'll lose quite a bit of weight too!
I can only speak for the G5, but changing from 17t to 18t front sprocket gives it slightly longer legs without any strain on the engine, happy all day at 60mph. The C5 has the same engine. Assuming the rear sprocket is also the same, I wouldn't want to go to 19t at the front. Might start getting a bit luggy.
There's a "might" for you right there. 

[Rattlebattle]

As I tried to make clear before, the C5 gearing is different to the B5 (and, apparently the G5 too). The C5 STANDARD sprocket is 18 teeth, so putting a 19 teeth sprocket on a C5 is NOT the same as doing so on the other 500 UCE bikes (again with the possible  caveat about the latest Euro IV models now being the same. The engines are the same but the rear wheel size on the C5 is smaller than the others, hence the differing sprocket sizes.

[Blairio]

I can only speak for the G5, but changing from 17t to 18t front sprocket gives it slightly longer legs without any strain on the engine, happy all day at 60mph. The C5 has the same engine. Assuming the rear sprocket is also the same, I wouldn't want to go to 19t at the front. Might start getting a bit luggy.
There's a "might" for you right there. 

When moving to the 18T front sprocket, did you have to lengthen your chain? Or did the available adjustment at the rear wheel accommodate it?
I am going to be pulling the RHS cover off to fit my Carberry anti-vibe (or is it?!) plate in a couple of weeks, so that would be the time to fit the larger sprocket. Mind you, I have a freer flowing exhaust (high level Hitchcocks scrambler one) however I still use the stock air filter. Maybe 18T is a tooth too far....

[Bmadd34]

I have fitted a freer flowing exhaust, bypassed the O2 sensor, and adjusted the TPS. My C5 has an 18'' rear wheel and 18 tooth drive sprocket stock.

[2bikebill]

Blairio - before I did any further upgrades (except suspension) I ran my G5 with just an open "silencer", 18t sprocket, stock air filter. It ran really well. No need to lengthen the chain for the 18t sprocket, although you have to pull the ends a bit harder to get the link in, but nothing tricky, and plenty of slack once it's on. I've just fitted a new 18t sprocket and chain, 101 again, no probs.

[Jako]

As I tried to make clear before, the C5 gearing is different to the B5 (and, apparently the G5 too). The C5 STANDARD sprocket is 18 teeth, so putting a 19 teeth sprocket on a C5 is NOT the same as doing so on the other 500 UCE bikes (again with the possible  caveat about the latest Euro IV models now being the same. The engines are the same but the rear wheel size on the C5 is smaller than the others, hence the differing sprocket sizes.

Yes the B5 has 19" rear wheel and 17 tooth,  but it seems most C5 owners opt for the Dunlop K70 tires once the originals have worn out , the K70 18"x 4" is 680mm diameter very close to the diameter of the 19" Avon's of a stock B5. Just saying to consider what tire you will be running in the near future before selecting sprocket size.

[Blairio]

Blairio - before I did any further upgrades (except suspension) I ran my G5 with just an open "silencer", 18t sprocket, stock air filter. It ran really well. No need to lengthen the chain for the 18t sprocket, although you have to pull the ends a bit harder to get the link in, but nothing tricky, and plenty of slack once it's on. I've just fitted a new 18t sprocket and chain, 101 again, no probs.

Thanks for the info. I reckon I'll give the 18t sprocket a go. At around 45 GBP it isn't a very expensive experiment, but  I need to be sure I have the correct socket for the sprocket nut (should do!).

[wildbill]

there were always mixed reviews on the forum if this 18t mod on a c5 was a worthwhile venture. I think the overall opinion was if it was mostly flat running it help calm the bike down and move vibration further up the top end range buy 3 to 5 mph.
if in hilly county I think there was mention you'd be working the gear box a tad more.
I actually bought the 18t from hitchcocks but never got around to fitting it on any c5. who knows maybe that time will come again..lol

[Rattlebattle]

You’d have wanted your money; C5 s come with an 18 tooth sprocket.... I’m still on the RoadRiders, which I’ll use again when the originals wear out.

[Rattlebattle]

...unless you are talking about a 2017 on Classic C5. Per Hitchcock’s:
Standard sprockets:
B5 and Electra all years: 17 tooth
C5 2009 - 2016: 18 tooth
C5 2017 on: 17 tooth
It appears therefore that the Euro IV 500cc models are the same with regard to gearing but they were different before. So putting a 19 tooth sprocket on a pre-2017 C5 like mine is similar to putting an 18 tooth sprocket on a G5 or B5. I hope this clears it up; if not I give up...

[Bmadd34]

When I contacted Hitchcocks they told me I needed a 19 tooth on my 2017 C5....

[johno]

I have an 18 tooth sprocket on my B5 (Original 17tooth) I have free flow air filter and free flowing exhaust.  a 102 chain fitted instead of the 101.
As may well know most of my journeys are of 100 mile plus on various road types.

Top end speed is not affected ie 82mph flat out
the resonance point has moved by 5 mph, which means comfotable 60+ mph cruising rather than 50-55mph. 70mph is a lot easier to maintain.
fuel economy remains the same

Hill climbing, as I can now achieve higher speeds in a lower gear it makes hill climbing ability on very steep inclines far easier, rather than sitting at 30 mph screaming the engine, I can get up to 40 in the same gear same revs if required.
Downside is that 30 mph in top gear is now to much of a struggle for the engine, so I wouldn't increase the gearing if your Enfield is mainly used at these lower speeds.