57.9 mph?????

steerpike

I did a longish ride today with some fairly steep descents. At times I was flying it but.....my Garmin 205 is trying to tell me my max speed was 57.9 mph?!?! It felt like I might have topped 40mph so I'm guessing something is going wrong with the calibration. All other data seems about on the nail though. Has anyone else experienced odd top speed readings from a Garmin Edge?

a_n_t

I managed 55.9 today with a serious tail wind on one descent so quite believable.

http://trail.motionbased.com/trail/activity/7005333

Alex_Simmons/RST

Those with power meters report that GPS-based speed readings on bikes are notoriously unreliable. If you want accurate speed readings, use a wheel speed sensor.

nevertheless, those speeds are possible but it needs to be pretty steep.

Lagavulin

I start throwing the anchors out at anything much above 35. :oops:
I've never experienced one but these so-called "speed wobbles" have me petrified.

cougie

You would know if you hit that speed. I've only got close to that on a 52*12 with gravity, and a tail wind.

Anonymous

Hmmm, you felt you topped 40 mph,

That would be about 64kphish....

Just sayin'

I've done 60mph on the road and it was the scariest thing I've done in my life. I used to be on a special ops squad in the police. Nothing there came close!

jojo90

spike or smooth ramp up? what about the altimeter, does that tally?

dannyg

I've got the Edge 205 which i use mainly offroad, but also sometimes to commute to work. I've had some mad speeds on it before, as mush as 240mph ish. So even though your 55.9 is possible, i'm thinking mine wasn't.

I often find that if you closely study the map download you sometimes get an area that has been missed, so the GPS jumps position, therefore giving you a false speed reading.

I have had it say 1400+ mph...it was having a really bad day that time, i'd also done 15000 miles on my way home which is usually only 4 miles

As said before, a wheel based speedometer is the only true reading, so longs as you calibrate it right of course

fnb1

I have recorded a maximum of 240mph (spike not ramp or cosnistent) on the Garmin 205. I suspect it may have been a slightly high reading, I don't think I was over the 100 mph mark.

chuckcork

I guess you could go that fast on a bike, but it would be a seriously steep hill and a long enough time to build up to it.

Yesterday I got to my fastest ever speed, 68.2kph (42.1mph), but that was pedalling down a fairly steep and long hill. If I hadn't been pedalling wind resistance would have slowed me down to less than that.

40mph sounds rather more accurate....

Simon Notley

a) It's quite possible to go that fast, I've been there or thereabouts but if you had been going that fast you would have known about it - it's a rush!

b) The Garmin can produce spikes if it momentarily loses signal - for example, I passed under an overhanging cliff edge at around 80 kph and the Garmin 'lost' me for a split second and the next reading was around 190! This only tends to happen at high speeds because the Garmin will know if it loses signal for anything more than a split second. It is also more noticeable at high speeds as the 'spike' is higher.

In summary, yes it's a spike - there's a big difference between 40mph and nearly 60!

hammerite

check your shorts, if they were soiled there was a good chance you may have been going that speed.

If not I'd say it was a spike.

passout

You would know if you were going that fast - blame the machine.

Cumulonimbus

The time gap thingy in the tour this year showed some jumps. I noticed one point on the Alpe where it suddenly changed by 20 seconds.This seemed to be near to hairpins so i guess maybe the GPS was having problems working out whether they were on their way into or out of it? Maybe this might be another cause for some of the dodgy readings? (i know that the motorbikes speeding along in front or stopping can cause the time gap to suddenly change but this was an instant big change)

TLA

Do you remember your cadence?

Assuming you have 700x23c tyres, plus a 53/11 gear combo, your cadence would have to be around 160rpm to reach 60mph (I hope my calculations are correct :oops:) Is that humanly possible?

Alex_Simmons/RST

TLA wrote:

Do you remember your cadence?

Assuming you have 700x23c tyres, plus a 53/11 gear combo, your cadence would have to be around 160rpm to reach 60mph (I hope my calculations are correct :oops:) Is that humanly possible?

The maths is about right. However at those speeds you tend to coast in a tuck as it's faster than trying to pedal.

Those cadences are definitely possible, ask anyone who's ridden a fixie with not such a big gear down a steep hill.

And sprinters on the track will regularly exceed 160 rpm for short bursts.

Nuggs

Did you fall off a cliff at around the time your computer registered 60 mph? That's the only way I could ever hit that speed!

John.T

I am never sure of how acurate these max speeds are. During the 2007 White Rose Classic my Hac4 showed I had a max speed of 66mph. This would have to have been down Dibbles Bridge hill as I know it well and did not touch the brakes until just before the bottom. I did not look at the time. When I downloaded the graphs they showed a max of 47mph. The Hac4 only records every 20 seconds but also holds the max readings on the head so it may have been possible. It could also have been a spike caused by outside interference. I don't know. I do know that I passed about 25 riders and no one passed me. This one will depend on who I am telling the tale to but I do not take the 66 as gospel.

guinea

TLA wrote:

Assuming you have 700x23c tyres, plus a 53/11 gear combo, your cadence would have to be around 160rpm to reach 60mph (I hope my calculations are correct :oops:) Is that humanly possible?

Yes. 160rpm isn't that high really. A few sessions working at it on the turbo should get your legs sprinting at that speed (and higher) without too much trouble.

However, I don't really think 60mph is something you're not sure about. It's very fast.

For me, 50mph sitting up and peddaling is slower than free wheeling in a tight crouch. I have poor flexibility and can't put much power down when tucked, but I've found it doesn't matter, on a large descent position is king.

blorg

Alex_Simmons/RST wrote:

Those cadences are definitely possible, ask anyone who's ridden a fixie with not such a big gear down a steep hill.

Indeed, I have a max of 189 RPM and regularly go in the 140-150 range coming down hills (46-17 gearing.)

The Garmin can be a bit unreliable at times, my max speed recorded on it is 5,301.8km/h. I am pretty sure I was not going that fast Actual max speed ever was 89km/h (55mph), down a steep hill, and I can assure you, you would know about it.

chriskempton

My Garmin once showed that a ride I did included a section at 4500m below sea level. I then climbed over 5000 vertical meters before stopping for a bite of flapjack.

You should have seen how many calories I used that day.

paulbricey

I''ve seen unusual stuff on Garmin 305 for both speed and height. Weird speeds seem to happen if the unit switches itself off during a ride (not often but seems to happen at random!) and I switch it back on again on the move - unit seems to think I instantaneously moved the distance while it was off

Richard_D

I have had my Cateye wireless record a max of 90 miles an hour on a couple of occasions. But I think that has been interference with with my HRM or local radio masts. especially as the other half only did a max of about 25 on the same run and she was cycling with me all the time. a 5mph difference I could understand but not 65.

floosy

I had the bike on the turbo last thursday and for a laugh I took all the loading off the wheel..

cadence got to 182rpm and speed sensor reading was 63.8mph.... so it is possible.. (50 - 12)

chuckcork

The specialized wireless comp I had before it went kaput used to go haywire at a particular corner on my way to work, while going through Richmond.

I thought I was doing great to get up to 70mph on the High Street under leg power alone!

Alas, just interference.!

peanut

I think body weight has a lot to do with it. I am very heavy so I get up to a good speed very quickly and maintain it longer. I've always flown past other riders who are 4-5 stones lighter.
Yesterday I did a modest 33mph on my regular route which didn't feel very fast to me .
Not sure I'd want to risk 60mph these days though :shock:

oldwelshman

In the marmotte according to my edge 305 I hot 600 mph!!
They are not reliable and can also record slower due to the sample rate.
Does it matter how fast you go?

ForumNewbie

I don't go very fast - max speed has been about 35 mph. Never had a problem with my Garmin showing false readings.

If you hit anywhere near 57 mph, surely that would be highly dangerous as I would guess that you have absolutely no chance of stopping safely in an emergency!

richlong28

i think its very possible

i've hit 35 going down a rocky desent on my mountain bike so i wouldn't be suprised if you hit 60 on a road downhill

(my computer says the fasted speed i've done is 57.7 but thats not right, not on a mountain bike)

tabmaster

I would seriously avoid going that fast if I were you... I used to hit about 50mph when I was a teenager and thought I was indestructable but since I grew up a bit and realised that I only have one life... I might add that I work in a trauma operating theatre so I fix broken people for a living - makes you think about what you are doing to say the least. I reckon if you come off at that sort of speed then you are dead as a dodo...

Sheptastic

i cannot get over 41 mph. maybe the rolling hills of the shire arent helping. time to move to scotland. or the alps.