gcb

Curious as to whether others have had this experience. In the past, I have always set my Gates timing belt tension with the Gates iPhone app but recently obtained a Krikit gage. I'm finding the Gates timing belt tension is considerably different depending on whether I use the Gates iPhone app or a Krikit gauge to set tension. I have two tandem bicycles equipped with Gates CDX timing belts. The belt tensions are considerably tighter if set at the recommended value using the Gates iPhone App vs using the recommended setting using the Krikit Gauge. (I am operating the Krikit gauge according to instructions; one finger, middle of belt span, etc.)

Examples (note: all measurements represent average values of 4 measurements taken with the crank rotated 90 degrees each time):

EXAMPLE 1 - BELT TENSION WAS SET USING KRIKIT GAUGE STANDARDS
Average tension measured using Krikit Gauge = 47 lbs (within 45-48 lbs recommended range)
Average tension measured using iPhone app = 25 Hz (well below 60-65 Hz recommended range)

EXAMPLE 2 - BELT TENSION WAS SET USING iPHONE APP STANDARDS
Average tension measured using Krikit Gauge = 114 lbs (well above the 45-48 lbs recommended range)
Average tension measured using iPhone app = 63 Hz (within 60-65 Hz recommended range)

I have tested this with 2 iPhones, 2 different Krikit gages, and 2 tandems. Always resulted in the same discrepancy between iPhone app and Krikit settings. I have come to the conclusion that the Krikit is giving me a “better” reading. The belt is less tight than with the iPhone app, but there is no ratcheting or slop in the belt and it does not feel like it is putting more pressure on the bearings than need be.

Anyone else notice this discrepancy between Krikit vs Gates iPhone app tension?

bobh123

I found using the app to be inconsistent and frustrating to use. I use the Krikit exclusively. It is difficult to read the Krikit, however, with its almost-invisible markings on the gauge and the place where the lever crosses the gauge often being ambiguous. It isn't well designed to read, but seems to be sufficiently consistent and reliable.

reburns

I don’t have a Kriket. I’ve adjusted my CDX timing belts to 40 Hz and never had any problems. 60 Hz always felt way too tight. Sounds like I could reduce tension even further if I wanted. The advice I received when I bought my first belt was to adjust tension so that you can hear a low bass tone when the belt is strummed, implying that hearing anything at all was good enough. Most people can’t hear below 25 Hz, so that’s consistent with what you’ve found.

Bellman

Don't use a device of any kind - just adjust by feel. Back in the early days (11 years ago when we started using belts), when there was no center track, I'd set them pretty tight. Nowadays with the center track, I keep them looser, but still tight enough to keep quiet and smooth.

merlinextraligh

This. Tight enough that it doesn’t skip, which is not that tight, and you’re good to go.

Alcanbrad

+1

PaulGrun

I gave up on the Gates iPhone app after my finger got raw strumming the belt trying to get any kind of a reading at all, much less what seemed to be reasonably consistent, and now just use the Krikit gauge. I am of the (uniformed) opinion that the tension doesn't matter too much just as long as the belt is tight enough that it doesn't skip but not so tight that the pedals don't turn smoothly.
I initially had the tension set too tight, so on our first couple of rides with a new bike it took me a few minutes to figure out that that new sound I was hearing wasn't the frame creaking ... it was the belt skipping. Tightened up a bit and haven't had a lick of trouble since.

merlinextraligh

This thread made me curious enough to pul out the krikit that came with our new tandem. To the extent I’m reading it correctly( agree with BobH about the ambiguity), the tension I set by feel on both our tandems is about 45 pounds.

I bet we could go lighter. But the tight enough to not skip, loose enough to not drag approach has worked for us for 13 years now.