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-   -   Attention KHS 2014 Flite 747 XXL & XXXL Owners w/ skipping chains- Problem Solved! (http://www.bikeforums.net/clydesdales-athenas-200-lb-91-kg/949187-attention-khs-2014-flite-747-xxl-xxxl-owners-w-skipping-chains-problem-solved.html)

svosho 05-20-14 04:08 PM

Attention KHS 2014 Flite 747 XXL & XXXL Owners w/ skipping chains- Problem Solved!
 
KHS 747 Flite Owners with skipping chain/shifts:

I am seeing other owners of 2014 KHS Flite 747's on this forum complaining of the same "skipping chain/shift" problem I experienced with mine.

I have your solution.

I ordered and picked up my KHS 747 Flite XXXL bike last month and immediately on the first ride the chain skipped mysteriously when giving the extra long 200mm cranks some forward pressure to pedal. I could lightly pedal with no skipping, but any real pressure on the pedal- even moderate- made the chain "skip forward violently". I realized this only happens when on the 52 tooth front big chainring. It never skipped while on the small 36 tooth front inner chainring. My LBS tried all sorts of adjustments to the front and rear derailleurs plus adjusting the barrel adjusters and even tightening the crank arms. It still skipped. We then put another KHS Flite 747 chainring on my bike that was on another new Flite 747 XXL in the showroom- SAME problem- skipping chain.

Here is the defect and the solve: The issue is that the big 52 tooth front chainring KHS installs is far too weak for us Clydesdales-period. When putting pressure to pedal the big chainring "bends" and lets the chain pop off the chainring and jump a tooth- rather violently. My LBS then switched the KHS chainring to a bone stock Shimano 50 tooth big chainring and I had no skipping at all- I could even stand on the cranks with all my weight- perfect!

Here is my permanent solve at my own expense- I bought new forged 52/36 chainrings from Praxis Works (about $165). Forged chainrings are the strongest for us Clydesdales and Praxis is the only (yes only) manufacturer of a 52/36 forged compact 110BCD chainring set in the world- I know because I did many hours of research to find this out! Shimano is the only other maker of forged chainrings in the world, but only makes a 50/34 Ultegra combo, not a 52/36. I installed the Praxis 52/36 forged chainrings on my Flite and it is sheer perfection. The shifts are perfection and I can stand on the cranks and have zero chainring flex. The 50/34 Shimano Ultegra combo will work perfect BTW if you want a setup better for hill climbing- you will just need to have your front derailleur adjusted and moved a little lower on the frame to accommodate the smaller diameter.

So, KHS seems to have sourced very cheap chainrings for these "Clydesdale-specific" bikes. I took it upon myself to fix the issue and don't want to point fingers at them. Heck, I am just glad I was able to find a bike for my 6 foot 8 body! KHS should take note though and just ship these with better chainrings- probably 50/34's as the smaller diameter will be even stronger. Yes, It would be ideal if they installed forged chainrings for us bigger folk, but that would add $100-$150 to the price. As I proved, even a mid-range Shimano 50 tooth stamped chainring was better than the stock KHS chainring.

So, if you bought a 2014 KHS Flite 747- change out the chainrings- both if you can afford a new forged set, but at least replace the 52 tooth stock one with a 50 tooth "standard" chainring. When I had the Shimano 50 tooth and the KHS 36 tooth combination on while waitng for my Praxis chainrings it seemed to shift just fine. If you cant afford that, have your LBS change the 52 tooth to a stronger 50 tooth and have them file a warranty claim with KHS ad they should really cover your switch to a stronger chainring. I am not sure you can find a 52 tooth "stamped/machined" chainring strong enough to handle our weight as the extra diameter is what may be causing the flex. If you want to stick with the 52/36 stock setup like I did go with the forged 52/36 Praxis forged- they are strong and don't bend! This is NOT a commercial for Praxis- frankly I wish I did NOT have to spend my money to fix KHS's problem, but i wanted you all to know how I got my Flite shifting perfectly!

Problem Solved!

Good Luck All!

chaadster 05-22-14 10:21 PM

:thumb:

WEK 06-12-14 03:29 PM

Did you mount and install the rings yourself, or have the LBS do it? And if you didn't do it yourself, do you think you could have?

H.S.Clydesdale 06-28-14 10:34 PM

:thumb:Thank You!!:thumb:

I am having this exact problem. I had been fiddling with my derailleur adjustments to no avail. I finally gave up and figured it was due to flexing of the frame. I had been researching carbon fibre thinking I needed a stiffer bottom bracket to accommodate the increased torque of the longer cranks. But this is way better! Cant wait to ride on the new chainring, as the bike is wonderful except that I can never really stand on it with my full force.

Any advice on where to buy these? I checked my usual spots and these chainrings seem to be hard to find.

WEK 07-03-14 01:09 PM

Quote:

Originally Posted by H.S.Clydesdale (Post 16891277)
:thumb:Thank You!!:thumb:

I am having this exact problem. I had been fiddling with my derailleur adjustments to no avail. I finally gave up and figured it was due to flexing of the frame. I had been researching carbon fibre thinking I needed a stiffer bottom bracket to accommodate the increased torque of the longer cranks. But this is way better! Cant wait to ride on the new chainring, as the bike is wonderful except that I can never really stand on it with my full force.

Any advice on where to buy these? I checked my usual spots and these chainrings seem to be hard to find.

Unfortunately (or fortunately, depending on how mechanically inclined you are) I've only been able to find them direct from Praxis online.

H.S.Clydesdale 07-04-14 01:10 PM

Yeess. Found a 52/36 set on ebay for $140.

http://i760.photobucket.com/albums/x...7-04115925.jpg

Just took it for a quick test ride, but so far it feels amazingly better. MUCH stiffer. Good thing I did not require a carbon fiber bike.

Interestingly, My bike had a 50/34 ring on it. Mine was a 2013 model. This required a more complicated install, but overall just took about 40 minutes. Well worth it, as now that I will be spending more time out of the saddle, I will enjoy the longer gears.

codysims 10-14-14 09:06 PM

Glad to find this thread. Got my XXL 747 home (bought in California, live in Utah) and had this issue immediately, doesn't even take much force to make it skip on (or completely off) the large chainring. Talked to KHS directly myself after getting an unsatisfactory answer through the dealer... was told there's been an issue with some chainrings. Not even sure it's worth trying to get fixed by them now, not sure I can trust this one anymore even if I get one that seems to work... I'll just order the strongest available. Gotta say, this is really surprising/disappointing for a bike made for big/tall folks. Thanks for the info svosho.

Here's a slow-mo video of the skipping (first clip) and jumping off (all the rest) that I took to send to dealer/KHS:

update
Getting a new chainring from KHS, the employee I talked to said they'd only seen or heard of this 3 or 4 times before, said 99.9% sure this would fix it. I'll try it out, but I also ordered the Praxis set, I'll probably end up using it just for sake of confidence.

fatpunk 10-16-14 09:47 AM

Wow, good to know. Thanks for the heads up, the 747 has been on my list for a few years now.

WEK 10-16-14 03:23 PM

Quote:

Originally Posted by codysims (Post 17217650)
Glad to find this thread. Got my XXL 747 home (bought in California, live in Utah)

Someone else in Utah has a 747? We must ride!

codysims 10-16-14 08:55 PM

1 Attachment(s)
Quote:

Originally Posted by WEK (Post 17223337)
Someone else in Utah has a 747? We must ride!

Nice, let's do it! I'm in Sandy. My username is also my twitter.

Props to KHS for getting me the new chainring via next-day-air. I was expecting an identical replacement and that's why I was apprehensive, but it's a different model - thicker & heavier.. and it solves the problem! So if you encounter this, hit them up for a replacement straightaway. I'm undecided if I'll use the Praxis set I ordered even though this one seems to work...
http://bikeforums.net/attachment.php...hmentid=412284

WEK 10-17-14 10:27 AM

Quote:

Originally Posted by codysims (Post 17224153)
Nice, let's do it! I'm in Sandy. My username is also my twitter.

Ha! So am I. Where do you like to ride? Not on twitter. Go ahead and send me a PM.

codysims 10-17-14 11:06 AM

Quote:

Originally Posted by WEK (Post 17225342)
Ha! So am I. Where do you like to ride? Not on twitter. Go ahead and send me a PM.

50 posts to PM (wow, restrictive)... username is also at gmail

WEK 10-17-14 11:32 AM

Quote:

Originally Posted by codysims (Post 17225493)
50 posts to PM (wow, restrictive)... username is also at gmail

Didn't realize that. Email sent.

XXLHardrock 01-29-15 10:08 AM

Can anyone tell me the largest tire size that will fit on the 747? Also, are there any fender/rack braze ons?
thanks

H.S.Clydesdale 02-03-15 12:07 PM

Quote:

Originally Posted by XXLHardrock (Post 17510965)
Can anyone tell me the largest tire size that will fit on the 747? Also, are there any fender/rack braze ons?
thanks

28c is the largest tire. 32c will clear in the width, but they will be too tall, and scrape the brake. You can see some detail pics of my rear 28c tire in this post:

http://www.bikeforums.net/commuting/...l#post17517040

You can also see the rear braze ons. They exist on rear dropout, but nothing on the rear stays. I dont think there are any on the front fork.

Cyclone_TS 11-18-15 01:07 PM

Well, I'm properly stoked to find people enjoying their Flite 747's. I'm new to to forum & have been searching for a stock tall bike for some time, as I'm 6'8" and am riding an aluminum 27" 1987 frame from Cannondale. It has the same chain skip issue as this, so I'll look at that next, but I'm stoked to have found a replacement stock bike in my size :thumb:


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