hydraulic hoses: psi and thickness?

[jn]

My L-900 has 3 sizes of hydraulic hoses.  As I understand it, the pump only puts out 1500psi. Shouldn't there only be two ratings of hoses, and those fairly lightweight?

i.e.: pump to wheel motors are heavy, 

foot pedals to accessories, bucket and lift arms are small,

steering controls are medium.

I can understand flow differences needing different diameters, but the hose wall strength varies a lot.

Two of my hoses need replacing and I would rather use lighter hoses where possible to fit into the small places more easily?

Is hose size really an issue?

Thanks

[mfmcallister]

Well for me it just came down to price and time. I blew out 2 original bucket hoses on my Dad's 46 year old L600 and decided to replace all 4 hoses. The originals were 3/8" hoses with SAE 37 deg(JIC) flare swivel female ends, 18" and 24" long. Buying standard 4000psi hydraulic hoses from Fleet Farm was $8.79 and $6.89 respectively. I ordered 3/8" female NPT to 3/8" female SAE 37 (JIC) swivel adapters for each end of the hoses. Amazon - $12.39 each, TSC- $8.99 each ( plus driving all over Iowa to find enough/ or buy with standard shipping and waiting.)  So cheapest price I can for hoses that will work is $24.87 and $26.77 respectively.  I ran out of time today, ordered parts are back ordered, so I called 8 hydraulic hose shops in and around Des Moines to get hoses made. A few quoted $70/80, one place offered 3000 psi hose for $45/48 and I would have to wait an hour once I arrived. The second to last place I called, Certified Power Inc. quoted $28 for 5000 psi hose, both lengths. I went there. It took longer to enter the order in the computer and pay for the hoses than it did to have them made. The hoses are overkill at 5000 psi but are more flexible than the originals and were easy to install. I wish I had made the calls a week ago but was told custom made hydraulic hoses would be too expensive. Not true...   Sometimes a thicker walled hose is cheaper that thinner walled due to popularity/volume sales. Rounder sourced the most common cheapest over the counter parts, at the time, so I'm sure some parts are too big/over kill for needs, however I would be cautious with changing hydraulic hose sizes. There are fluid dynamics issues involving flow/resistance and heat buildup if you under size the hoses.