Why many rear racks no longer triangulated?

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NetworkMan
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Re: Why many rear racks no longer triangulated?

Post by NetworkMan »

Compelling case? -probably not; but In terms of power consumption that amount of aero drag is about 1% of a typical tourists output. To put it into perspective this would be similar to lugging 1kg extra up every hill; the kind of thing that weight weenies (and even some normal folk) spend a fortune trying to avoid, or they will spend cash on better tyres for a similar benefit.
cheers


Perhaps it should be noted and considered as part of a package of weight reduction/rolling resistance/aero improvements. These might be insignificant on their own but might be noticeable when taken together.
Brucey
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Re: Why many rear racks no longer triangulated?

Post by Brucey »

re noises; if you have a quiet-running bike and ride in quiet places, you hear all kinds of things. For example most years I take my dynohub wheel out of the 'training' bike in the summer, so that I can overhaul the hub (it lives out of doors and tends to accumulate rust inside no matter what I do with it). The stand-in wheel varies but it is often a wheel with aero spokes. The bike (which has mudguards, exposed cables and goodness knows what else) is noticeably less noisy with the aero spoked wheel fitted.

In fairness most derailleur gears are so noisy that you wouldn't hear such sounds whilst you are pedalling; it takes a derailleur geared bike with an almost silent freehub, freewheeling, for such sounds to be clearly heard.

cheers
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mercalia
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Re: Why many rear racks no longer triangulated?

Post by mercalia »

re noise. Well I had a listen on the ride to the shops. My freewheel is one of the clickless quiet ones. all I could hear apart from the tinkle of my bell as I went over bumps and the wind in my ears, was the noise of the tyres on the road.
kwackers
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Re: Why many rear racks no longer triangulated?

Post by kwackers »

I once carried 4 x 20kg bags of cement back on my blackburn rack.
(two strapped to the top and one in each pannier - Ortliebs - wedged in and poking out the top).

Triangulated or not, I was really concerned that the rack wouldn't make it. It and the bike had side-to-side momentum like you wouldn't believe.

Funniest thing ever, in a moment of unthinking madness when I came to a bicycle gate that I'd normally go through by flipping the front up, I flipped the front up to be immediately thrown back off the bike whilst it assumed a new pose sat on it's bum.
Last edited by kwackers on 19 Sep 2019, 6:20pm, edited 1 time in total.
Bmblbzzz
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Re: Why many rear racks no longer triangulated?

Post by Bmblbzzz »

:lol:
I think that journey probably would have justified a trailer!
Samuel D
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Re: Why many rear racks no longer triangulated?

Post by Samuel D »

… and a team of oxen.
mercalia
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Re: Why many rear racks no longer triangulated?

Post by mercalia »

Bmblbzzz wrote::lol:
I think that journey probably would have justified a trailer!


I once did some thing similar taking 8 or so 5l ex m/c oil containers full of used m/c engine oil to the local recycle centre. I did use my trailer though. could have been a real mess had they leaked over the road....
Brucey
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Re: Why many rear racks no longer triangulated?

Post by Brucey »

mercalia wrote:re noise. Well I had a listen on the ride to the shops. My freewheel is one of the clickless quiet ones. all I could hear apart from the tinkle of my bell as I went over bumps and the wind in my ears, was the noise of the tyres on the road.


Maybe you weren't going fast enough, or maybe your tyres are very noisy....? But seriously, if you remove a lot of stuff off your bike it usually runs more quietly. Aero wheels can be quite a bit less noisy. However if you are in a city the level of background noise may swamp the noises from your bike. Note also that you will need to turn your head to one side so that the wind isn't making a noise in your ears, if you want to hear anything useful.

cheers
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NickJP
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Re: Why many rear racks no longer triangulated?

Post by NickJP »

SA_SA_SA wrote:It seems many rear pannier racks are no longer triangulated despite having enough struts to make it easy:

I wonder why?

I think that the necessity of triangulation depends on the materials and diameters of the struts used in the rack. When I first started touring in the 1970s, I used a Karrimor pannier rack (not triangulated) made from fairly small diameter steel rod that was plastic coated, and it would waggle a bit when loaded and subsequently broke. I then fitting one of the Blackburn triangulated aluminium racks. It lasted several years before it also broke. I then lashed out and purchased a pair of Bruce Gordon racks brazed from 10mm CrMo tubing without any triangulation in the rear rack, and that rack is still going strong over 35 years later, and has been used on numerous tandem tours where we're carrying cycle camping gear for two people.

The corresponding Bruce Gordon CrMo lowrider front rack does have some triangulation in the form of the loop going over the front wheel that connects the two sides of the rack. In fact, if we're on a tour where we're not carrying gear for camping, I have a pair of humongous home-made front panniers that can swallow everything needed for two people for several weeks, and we carry everything on the front. You can see that on this tour, the rear BG rack was carrying nothing more than two pairs of sandals:

Image
Last edited by NickJP on 23 Sep 2019, 9:33am, edited 2 times in total.
Bmblbzzz
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Re: Why many rear racks no longer triangulated?

Post by Bmblbzzz »

The OP doesn't seem to have been back to give his own views on triangulation or even tell us in which sense he was thinking of it. Which is a shame.
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andrew_s
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Re: Why many rear racks no longer triangulated?

Post by andrew_s »

Vantage wrote:As network man already stated, if you look at a rack from behind as its fitted to the bike, you'll see the struts either go straight up at 90° which isn't triangulated, or they'll go up at an angle towards each other which is triangulated.

Triangulated, in the sense of a bike rack, means that if you look at the rack from the rear, you can see that the stays on each side of the rack make a triangle on each side, because one pair of stays joins the rack top closer to the centreline than another pair.
See the drawing of a Tubus Cargo here: https://www.tubus.com/fileadmin/user_up ... TZ_1.0.pdf

The triangulation makes a heavily loaded rack more resistant to moving from side to side (notably when climbing out of the saddle).

I would suspect that many racks aren't triangulated because it makes robot production simpler.
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Vantage
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Re: Why many rear racks no longer triangulated?

Post by Vantage »

Isn't that what I said?
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NetworkMan
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Re: Why many rear racks no longer triangulated?

Post by NetworkMan »

Vantage wrote:Isn't that what I said?

I think so. It's what I said in post no. 5 along with an example of the Blackburn! This thread is becoming a touch repetitive methinks!
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The utility cyclist
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Re: Why many rear racks no longer triangulated?

Post by The utility cyclist »

NetworkMan wrote:
mercalia wrote:what does triangulated mean? a picture of both would be useful?

Two of the struts meet the top of the rack close in to the middle so that viewed from the rear they form a triangle with the base at the bottom.
Edit: This Blackburn is an example. It's somewhat triangulated.
https://www.amazon.co.uk/Blackburn-Expe ... B000NORUTM

IMO that's a weak triangle design as the angles are too acute with unbraced longer sections which increases chances of bending compared to the one that Mercalia has which is similar to my lightweight 'muddy fox' branded rack, thats likely from the early 90s and still going strong (it came on a bike I bought a dozen or so years ago)

I currently use a Tor-tec Velocity hybrid on my Globe Expert drop bar conversion which gets used for pretty much everything, though the narrower top does limit it in terms of strapping lawnmowers, childrens bikes and car wheels on it (which the Muddy Fox deals brilliantly with), it's rated to 25kg though taken more a fair few times without issue and gets loaded to 80% of its capacity fairly regularly.

If it breaks after 10 years I'm not going to be upset as it was £20 new, obviously if people want a 'proper' :roll: rack that is rated to a higher load then get what suits your need but the whole non triangulation thing in terms of what you've pictured is no big deal and as I said what you did picture is weaker in any case IMO.
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The utility cyclist
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Re: Why many rear racks no longer triangulated?

Post by The utility cyclist »

Brucey wrote:it appears to be about the same cost as a posh tubus; not an awful lot more, anyway.

The other thing I have often wondered about is why QR racks are not more common than they are.

cheers

Because they are more rattly/wobbly/less load and generally inferior IME, they're a faff because you're fitting/unfitting regularly and not to mention easily stolen, I'd never have one.
My tortec velocity never makes a sound, the bike it's on, 95% of the time I have a bag fitted which I take because I have a rack fitted, it's that narrow so behind my body/legs and weighs less than even a basic lock, that I simply don't notice any extra drag, I would think there's far more just from the front mudguards anyway. I'd rather have a solid permanent rack than a QR that I would feel I'd have to remove/refit because otherwise what would be the point buying it.
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